Anyone know why with windows 8.1 Adobe cannot sell me a PS CC 2018 which would install?

The supported versions, which come in the subscription and can be downloaded from the CC desktop application, are the current and last versions. They are:

v20.0.8 which requires Windows 7 SP1 or Windows 10 (1709 or later)

v21.1 which requires Windows 7 SP1, or Windows 10 (1809 or later)

v19.1.9 cannot be downloaded from the CC app but if already installed (and not removed when updating) will continue to work. It requires Windows 7, Windows 8.1 or Windows 10 (1607 or later)

We are not Adobe employees so cannot comment on why support for Windows 8 was dropped.

Dave

Neither Microsoft or Adobe support Windows 8.1. You need to upgrade to Windows 10.

Do you mean a perpetual license? 

Adobe stopped selling those back with Photoshop CS6. 

Edit: I had missed Ged’s post. 

Hi

Adobe do not sell perpetual licences for CC apps, if you have a Creative Cloud subscription you can download CC 2018 from here

https://prodesigntools.com/adobe-cc-2018-direct-download-links.html