This is a false fear. The real risk isn't that some 19 year-old vibe coder is going to replace you, it's that there's simply less need for more experienced engineers. The market is shrinking.
Also, even if the premise behind the SaaSpocalypse is naive and oversimplified (companies aren't going to replace all their SaaSes with internally vibe-coded replacements), it looks reasonable that net-net AI will have a negative impact on the value of software.