There were a few reasons back in the day that I did not update.
1. Older versions had weird origin or image_xscale differences (cant remember which) that made updating annoying at the time.
2. Back then I used the sprite editor as my primary way of creating sprites, and newer versions broke the sprite editor for about 3 years straight (Every version after that had broken lines in the sprite editor when drawing with the pencil.)
I don't know if it's been fixed now, but it resulted in me not upgrading for years. Any new projects were made on Studio 2, and all old projects remained on the older Studio version since I saw no practical reason to upgrade.
And yeah, I do have a License for studio 1.
Edit: I looked up an email where I asked them about the editor problem, the version was
1.99.355 EA
Also I just noticed that I can't even try older 1.4 downloads? What's up with that?
It's not uncommon to stay on an old version of software until a project is done and shipped, so it kinda seems like that decision is going to screw over a lot of people with existing projects. It's not just a matter of getting updated features.