Affinity Photo is a credible alternative to Photoshop for many uses. However, Photo is not 100% feature equivalent to Photoshop which means it won't meet everyone's needs. You can certainly use Affinity Photo for professional results. For examples, see: https://affinityspotlight.com/articles/tag/affinity-photo/
Affinity Photo, Designer and Publisher are all cross-platform (Mac and Windows) and are not based on a cloud subscription model. They are also substantially cheaper than Adobe apps.
The Adobe app that truly has no rival is After Effects (AE). There are alternative apps for creating motion graphics or visual effects, but nothing can match the range of features that AE encompasses.
A related, but important point about Adobe: the dominance and longevity of their apps mean the learning resources are simply unrivalled. There are probably more tutorials for Photoshop than any other piece of software ever. That volume of learning - from beginner to advanced, and to high-specialised use cases - is enormously appealing to all users.
As in, there's going to be a lot of places/work where "Photoshop" and a few others are it. There are FOSS alternatives, and some very good ones at that, but they're not used in the majority of professional contexts.
The problem, though, is that would imply there being no need for such an ugly cancellation process. It would be less costly to make cancellation simple. Skip all of the UX dark-pattern research, A/B testing, metrics/telemetry used to hone that process to reduce cancellation and just give 'em a button.
For commercial/professional users in some contexts, you're almost certainly right -- they're not switching to something else any time soon. But I have to believe this nonsense was put there for reasons beyond those users. I think back to my Dad, who purchased the full Adobe Acrobat suite in the mid 00s (something like $500/pop) because he didn't realize he could fill in Acrobat forms for nothing. I wonder how many users of CC are in my Dad's shoes, in which case these screens -- last-ditch efforts to "sort-of scam" a customer into staying -- make more sense.
[0] Try Adobe Experience Manager one day. No. Don't.
That hasn't been the case for quite a while. There is plenty of software, typically with much lower cost or even free in some cases, that now provides a credible alternative to Adobe CC applications for many users including professionals who have real work to do.
Figma
Sketch
Affinity
Blender
Photopea
VectorStyler
Vectornator
It's not 2010 any more.
Obviously these alternative products all have their own strengths and weaknesses and features and limitations. So do the CC applications. There are plenty of cases where one or more of the alternatives actually offers better functionality and/or UI these days.
Sick of Adobe's greed-driven lack of respect for customers.
Also, after interviewing with Adobe (granted this was 3-4 years ago), I was not impressed. I was asked who I voted for in the 2016 elections.
If Adobe was content to only target the content creator market then they would be putting more effort into distinguishing their product and less effort into trying to frustrate users into submission. It's a numbers game and their biggest markets are not ones that use the software for professional content creation.