Indeed - and actually, the running of the thing is probably harder than building it - not least because you run it 24x7, forever, whereas you may mostly build it for (say) 6 months of 8x5, and then can drop to minimal development operations after that.
The "saaspocaypse" isn't really real. What is happening is that people are realising that a lot of the "big boy" SaaS products are pretty crappy, cost a fortune and actually aren't necessarily run all that well. They also need a load of full-time "devs" to make them do anything useful, and so the ROI on them isn't nearly as good as it should/could be.
If you're a small or medium sized business, you definitely do not want Salesforce, Servicenow, etc - you want a far, far simpler system which feels like you're going to outgrow it in the next year or so. In a year or so, you won't have outgrown it at all - but you will have saved a tonne of money. The really big guys might well build their own, and it might be a way for them to (finally!?) properly personalise what they do for their customers, but they sure aren't going to be "vibe coding it in a weekend" - it'll take longer than that, but it is perhaps more accessible now than ever before.
I've said it before, but I predict the opposite of the SaaS-pocalypse - actually, I see an explosion of SaaS apps coming - with the barrier to entry reduced significantly, a load of new products will come along. Sadly, 80% of them will be PoCs dressed as finished products, and will likely fail spectacularly within a year or two. The remainder though will likely be small going-concerns, but service a loyal customer base, "do one thing, do it really well" and hopefully properly nail the customer service to deliver some real value.
Someone on Linkedin was rattling on about how there are going to be a rash of single-person billion dollar companies because we're all going to be making apps now - I seriously doubt that. If it's easy to do, then it's not going to be worth the billion, but it could be a very nice living for a decent number of people, and maybe some "a few million" sales and IPOs for a very small number, followed by the requisite enshitification and exodus of the loyal users that made it, etc etc.