Not even just the customer-facing stuff either, the internal tooling is on fire more and more often. It's not sustainable in the slightest
If they are vibe coding anything, it hasn't had any bad consequences yet. The ads and bloat are human decisions!
Another kind of highly valuable software is a new design which digitizes some process, like the ticket management of a rail company. If you don't follow the internal processes and workings of the firm exactly, or you do not interface with existing systems 100% accurately, your software very soon becomes worthless.
Figuring out how to create a piece of code that solves the exact problem the customer has, while not breaking anything, and fitting into existing operations seems to be a big head scratcher still, and something humans still need to do, at least that was my experience so far with LLMs.
... as long as the buyers could never discern
Low quality ends up taking longer to build over the long run. It gets harder and harder to add or change features.
If you need it to work for at least a month or two (instead of one and done, which some demoware is like). Following a few rules early on will ensure you can keep evolving it — even if it's MVP/demoware/whatever — as long as you know you need to evolve it soon after you build it!
In tech, the era of competing based on quality is long gone. The winning strategy is to get a monopoly/oligopoly and then you can let the quality decay to zero and people will have no choice but to keep paying you money (or to your handful of equally-mediocre competitors).