The truth of the matter is that software starts as basic CRUD and then given time and users evolves into its own special snowflake. Every single system given enough time and users will become a “complex system”.
Which as you yourself just said are not conducive to PM vibe coding.
Sure, most business needs only have a few users. I once built a dashboard over the course of a year only for a grand total of around 10 business executives to actually use it.
If you are looking at just number it apps things like that might actually be 90% of all commercial applications out there. But if you look at where developers spend there time it just number of devs working on them, it’s nowhere near 90%.
There is some subset of applications that is too complex for no code but not too complex for vibe coding. If that was the niche you were working in you might need to find something else, but I’d be shocked if that employs enough people to have a negative impact on overall software dev job/salary growth.