Acquiring Adobe would eliminate one of the most notorious rent-seekers in the industry and make Apple’s service offerings even stronger. Apple can be annoying at times, but when it comes to subscriptions, they’re the complete opposite of Adobe.
Windows still has close to 80% market share (probably higher if you focus on Adobe's bread and butter - enterprise accounts).
Adobe would be an incredibly expensive purchase for Apple, and if would potentially lose 80% of it's value overnight if they tried to make the product proprietary. They may as well purchase a different random company like Autodesk or Palo Alto or Intuit for the same or less money.
And FWIW Adobe is highly intermingled with Microsoft already - they consume lots of each other's services and are much more aligned in business interests.
I just read a 1980s article in Byte magazine about the difficulty of the pre subscription software business. Back then you raised a pile of money to make version 1.0 and maybe you really made it and then you raise money to market it and maybe you made a profit and which can you put some of that profit into version 2.0 and your version 2.0 competes with everything on the market but most of all the version 1.0 that people are still using.
For a software developer it is a precarious life full of crunch time and no matter how nice your employer is they are at risk of running out of money and not being able to pay you, Contrast that to SaaS life where the money is predictable and thus your life is predictable, no having to always catch up with you what you promised in magazine ads six months ago or to demo at a trade show, whatever.
Sure Adobe is soaking customers but the predictable money makes it a much better place to work. Back in the day you had to shell out $1000+ for the Creative Suite, now it is a monthly payment more people can afford to make and you may be paying more in the long term than if you bought version 7.3 and never upgraded but you are paying less than it cost to stay up to date.