I use both (Sketch and Adobe apps) for their different use cases bases on as needed.
Adobe single app doesn’t costs $40/month but ALL APP pack at $49.99/month. However, yeah, still a lot more expensive than Sketch but we have to remember, sketch is not a cross platform app (yet) ☹
Adobe Photography plan costs $9.99 that includes photoshop. You can choose any single app (e.g. Illustrator, InDesign etc.) at $19.99