OP is lamenting that Cursor and OpenAI chose to create new apps instead of integrating with (someone else’s) existing apps. But this is a result of a need to be always fully unblocked.
Also, owning the app opens up greater financial potential down the line…
Few people outside of tech circles know what those other apps you mentioned are. I use Confluence at work, because it’s what my company uses. I also tried using it at home, but not for the same stuff I’d use Pages for. I use Obsidian at work to stay organized, but again, it doesn’t replace what I’d use Pages for, it’s more of a Notes competitor in my book. A lot of people don’t want their documents locked away in a Notion DB, and it’s not something I’d think to use if I’m looking to print something.
I went back and looked at the last WWDC video. Apple did mention the apps briefly, to say they have integrated Image Playgrounds, their AI image generation, into Pages, Keynote, and Numbers. With each major upgrade, the iWork apps usually get something. Office productivity isn’t exactly the center of innovation these days. The apps already do the things that 80% of users need.
I agree with you on where OpenAI will/should sit in 5-10 years. However, I don't think them building the occasional tool like this is unwarranted, as it helps them show the direction companies could/should head with integration into other tools. Before Microsoft made hardware full time, they would occasionally produce something (or partner with brands) to show a new feature Windows supports as a way to tell the OEMs out there, "this is what we want you to do and the direction we'd like the PC to head." The UMPC[0] was one attempt at this which didn't take off. Intel also did something like this with the NUC[1]. I view what OpenAI is doing as a similar concept, but applied to software.
[0] https://en.wikipedia.org/wiki/Ultra-mobile_PC
[1] https://en.wikipedia.org/wiki/Next_Unit_of_Computing