I think opensource is a good analogue here. For many SaaS products, you don't even need to vibecode anything - there is already a reasonable OSS alternative. Yet people still pay for the SaaS. They want support, maintainability, security, edemifcation, a throat to choke, regulation and domain expertise, etc.

I do think like this HN post (https://news.ycombinator.com/item?id=46847690) is a good example of where a custom more domain specific solution makes a lot more sense that dropping in an off-the-shelf ERP. Still though, I think the bakery would prefer to buy the bakery-ERP than build it but vibecoding does reduce the barrier to entry so we might see more competition and share taking from incumbents by domain-specialized new entrants.