AI isn't even eating most shitty SaaS businesses, because it's a weird HN fantasy that your hairdresser or car mechanic are itching to manage agent swarms and risk losing their business if that unnecessary adventure goes sideways. They would much rather pay several hundred bucks for a SaaS product that has a bunch of UI annoyances.
It's likely that there will be an explosion in vibecoded competitors to existing SaaS products, but I wouldn't underestimate the importance of familiarity and stability. I use a bunch of SaaS stuff for my business and it's not like I do a weekly comparative analysis to see if switching to some unfamiliar platform that popped up overnight could save me a bit of money or time. It's just not worth it.