P: Please let us make "destructive" changes to our images

The "strong reactions" are caused by Steve's lack of understanding of the overall design philosophy of Lightroom.  Also, Steve always has the option to do a one-time TIFF export of each of the images in question and use that TIFF for further non-destructive edits.

I don't agree with everything Adobe does, for example the confusing announcement of Lightroom Classic, but I would back Adobe 100% in not addressing this request.

Steve,

Please don't confuse your specialized requirements with those of the user base as a whole.  Listen to what people are telling you.  Go with Photoshop.

If it was easy, then it should not be too difficult for a programmer to write a plugin to do the job.

I don't understand the strong reactions to Steve Martin's reasonable proposal?   The current non-destructive editing should be the default of course.  Should it be easy to accidentally save destructively - absolutely not.  Should it replace RAW files, eg with jpegs - no need.  No one who currently uses non-destructive LR should be inconvenienced in the slightest.  As pointed out this is certainly a trivial programming challenge.  So why not offer it?  Or if this is such a sacrosanct photo editing feature, why not insist Photoshop not be allowed destructive editing?

To be more clear about these different things.

RAW files format are the property of every camera producers. And they keep their file map secret. It go so far that within the same product range (like 1D MkIV and 5D Mk III) RAW files structure can be different. Every producer has it's own RAW format type. In other words, a Nikon camera can't read or create a RAW based on Canon RAW format. 

A RAW is NOT a RASTER or Vector format, it's just a binary format that need to be interpreted by a software like the one you have on your camera. This soft create a JPEG. due to it's simplification, it's almost difficult to make good corrections on it while wit a RAW almost every elements are adaptable. RAW format is to be considered as the image source.
  
As They are badly documented, every software maker need to make reverse engineering to be able to read the different format. But they will never adapt it. They will create an other file style TIFF - JPEG, etc... 
To my knowledge, it doesn't exist a software producer having directly received the complete map of a RAW format from a camera supplier.

To add on this, old photographers like to keep their RAW just as they did for analog negative.

In EDP world, one say " In any situation type keep your original free off ANY changes" So said RAW is the basic reference for most of photographers. Most of them need to keep them un their hand.

Keeping RAW format files, is also some times an advantage depending on what job type the photographer does. 

Do not forget to think about new software version. Evolution....

Your considerations:
You cannot compare RAW and previews. Their purpose are radically different. RAW needs a Preview to be seen. Preview is created each time you act on the RAW while the RAW is kept free of any transformation way of doing preparing the resulting file differs from one soft to an other.

Comparing Picasa and LR is a non sense, they customer target is to my opinion different.

Everybody has the right to erase every thing on it's computer, as well as the RAW.  It's not a question of right it's a question about conception.

To finish on this point, if your last proposition should by hasard be applied, I will be very sad for the users of it. They will create a mess on their computer. Several users are already doing this mess. But without any protection (guide line) this will be a disaster. 

You CAN'T save changes to RAW files (although the original camera vendor would have the RAW specs and could presumably do so if they wanted- but Adobe can't.) So your idea is impossible from a technical standpoint.

Thanks for your thoughts. Maybe Adobe could save the original in the catalog somewhere, like they do the Previews, when one chose to overwrite. Google Picasa almost had this right but the .Picasaoriginals folder they created was in a subfolder directly under the image that was changed, causing clutter. I did roll back a few times, but mostly just deleted the .Picasaoriginals folders after some period of time.

All that conversation for 7K pictures! I wonder which corrections you are making on such light pic's?
My estimation is that LR does what it has been conceived and written for what it does today. Flexibility is there in LR, one can adapt the way of use based on it's own specific needs. Yes, as every application, LR is not 100% perfect. For sure, depending on users styles, there are several aspects to be improved.
But, I find that your suggestion will open to a messy situation within catalogs. Best is to keep it as it has been conceived from the beginning.

Any way, there is a simple way to solve your situation. You describe it.

What evidence? The entire history of Lightroom, and the entire history of Photoshop's own Camera Raw plug-in that preceded LR, and which it's based on. You ask any of the people who were there at the start... oh hang on, you just did.

The beauty of non-destructive editing is that you are not locked into 'one edit and you're done'. You can come back to an image later, add to it or rework it completely. Over the years, Lightroom has had, and will continue to have, new tools added to it. The ability to go back to an original image and improve it with new tools or even newly learned techniques is a huge advantage. Destroying your original files, even if jpeg, is not a good idea for Lightroom.

You don't have to be a pro to shoot raw, you just need to realise the huge advantage that can be gained from working with all the captured information, rather than a compressed file that has had a large proportion of image data discarded by the camera's software. Editing raw is no different to editing jpeg in Lightroom, but the results can be enormously different.

A destructive workflow make no sense to me. Even if I used a destructive workflow, I would make sure my original files were never touched (backed up, archived).