(Notion + Workspace would be an incredibly strong offering for startups ... if it was all integrated/owned by the same company)
I've also always felt that Dropbox should have went down this road, after they released Paper in 2015, but I think their time has passed. Google also wasn't nearly as vulnerable back then; they still aren't super vulnerable now, but I think they're trending that way, and if Notion times it right they could be in a great position.
Also, "AI" in it's majority current form, has been around for decades it's just cool now to use the word "AI" when branding a product/company.
Great when you share notion pages with clients during a video call and that pricing banner hangs around. We are looking to move off Notion now, not because of the banner, but it definitely contributed.
I love Obsidian and I really wish there was an enterprise-level hosting option for it.
[0] https://relay.md
After trying Notion and experiencing the 'lock-in' for myself, I switched to Obsidian years ago - no regrets. Combined with Syncthing, it works surprisingly well - offering graceful/seamless editing of the same Notes across Windows desktop and multiple Macs, updating to the other devices in essentially real-time.
If anyone uses Notion and really cannot stand their UX, I'd strongly recommend Whimsical: https://whimsical.com/ -- it can do a bit of Trello too.