It would be nice if Photoshop wasn't bloatware.

No, it's not bloated. It's professional-grade software, and like all professional software it makes no allowances for limited hardware resources. It's designed for heavy duty workloads.

There are functionalities in Photoshop I myself do essentially not use – DICOM stuff comes to mind. 

So while some might call that »bloat« experience seems to indicate that no matter whether one feature is irrelevant to oneself there may be others to whom it is relevant. 

Adobe took away my permission to use Photoshop CC 2018. The program now opens as the trial version. When I try to sign in because I have a subscription it says the license is invalid "because we no longer support new activations of outdated software and apps."

By @MagicalSakura

This doesn't make any sense. This is not how CC licensing works. Obviously, you can keep using CC 2018 and it's not "invalid".

Something else is going on here. If the OP shared some more information we might be able to figure out what. A good start would be screenshots of the messages that come up when trying to sign in.

No, it's not bloated. It's professional-grade software, and like all professional software it makes no allowances for limited hardware resources. It's designed for heavy duty workloads.

@Shivangi_Gupta , please forgive the intrusion but I found posts of yours referring to the use of obsolete application versions, so maybe you can shed light on this: 

Does Adobe disable the licensing of obsolete (but existing and operational) installations of Photoshop (CC 2018 in this case)? 

The OP’s statement »Adobe made it so I could no longer use the software despite my subscription« is not completely clear to me but my understanding was that as long as the OS, processor, … met and did not exceed an obsolete Photoshop CC version’s needs that version would continue working. 

Adobe took away my permission to use Photoshop CC 2018.

Adobe doing that is news to me, but the oldest version I still have installed on an old computer in the office (and that can run with the OS on that computer) is CC 2020 and that is unaffected. 

So you definitely did not change any component of your setup (OS, hardware, …) but the CC license just didn’t work anymore for the obsolete Photoshop version? 

Adobe took away my permission to use Photoshop CC 2018. The program now opens as the trial version. When I try to sign in because I have a subscription it says the license is invalid "because we no longer support new activations of outdated software and apps." They do not allow you to run obsolete versions of photoshop which is my expressed frustration. If I was allowed to continue running the older version that required less RAM I'd be very content.

I do not believing in having to update my hardware every couple years to support a bloated subscription program. My OS is up to date. Creative Cloud was the first thing I updated when they took away my permissions to use Photoshop 2018. No matter what I do, they do not allow obsolete version of the program anymore because it's at it's end of life.

As for insolent language, I feel no reason to be more polite to a company that responded to "Is the only way to keep using the 2018 version by pirating it?" with "If that is available you should do that." 

It's also bloated because of how much RAM it uses. It takes up 40-50 gigs of hard drive space by just opening the program. The features aren't why I'm calling it bloated. I'm calling it bloated due to poor optimization and inefficiencies in how it operates. The new features? Fine. The amount of RAM each update requires is getting ridiculous. Currently, the most recent version of Photoshop has 8GB min and 16GB recommended which means you actually need 32GB for the program to run smoothly.  

I also don't see why you would bing up an NDA of an employee from a company that tells its users to just go pirate their software instead of allowing for the use of obsolete versions of their software that run better on their PC.

How did Adobe make it that you cannot use Phothsop CC 2018 anymore? 

Did you upgrade the OS, the hardware, …? 

So far it seems to me that obsolete Photoshop versions run fine as long as the OS etc. do not exceed the original System requirements. 

The question »Why is Photoshop so bloated?« seems pointless. 

Firstly: Who is to say it is bloated? Just because you don’t like certain new features doesn’t prove they would not be useful to other Photoshop users. (And please refrain from using insolent terminology.) 

Secondly: Adobe personnel reading your post would be subject to NDAs and thus »those that know don’t tell, those that tell don’t know« would seem to apply.