Lets take Figma as an example, Imagine you have 1000 employees, 300 of them need Figma, so you are paying 120k per year in Figma licenses. You can afford 1 employee working on your own internal Figma. you are paying the same but getting 100x worst experience, unless your 1 employee with CC can somehow find and copy important parts of Figma on his own, deploy and keep it running through the year without issues, which sounds ludicrous.
If you have less than 1000 employees it wouldnt even make sense to have 1 employee doing Figma
I mean in an example that almost happened... "you are paying 120k per year in Figma licenses, Adobe buys it, you are paying 500k per year in Figma licenses"
At least up until the point of vibe coding it was still worth the SaaS provider charging at least as much if not slightly more than you doing it yourself because most businesses weren't going to anyway.
If you need rich outputs, there are tools for that now too.
Let me put it another way - would you want to be Adobe or Figma right now?
And applied to the original point, would you feel comfortable being a SaaS company right now?
So you end up spending the money elsewhere? with exploratory design you can easily spend 10k a month on these models as a company of 1000, thus completely losing any monetary savings. Anyway you look at it, Saas worked because costs were spread out and low enough to not optimize it too much.