The problem with the idea is that there is no right solution. What they do are free alternatives. Free software is not a new idea. Secondly, even if SaaS companies get all developers back then competitors with less devs may be more agile as they as well have AI tools and without all this people be more lean.
If anything, regulation is the more realistic solution. Requiring licensed CS/CE/STEM engineers (a degree plus a licensing exam, likely one for the US and a separate one for the EU) to sign off either manually written or generated by AI output on software in critical areas like healthcare, finance, insurance, energy, government and infrastructure, or above a certain revenue or valuation. That would keep people with verified skills in demand and improve security. Anyone could still build yet another SaaS, custom apps or games, and teach themselves along the way. They'd just need to hire licensed specialists once they grow or handle sensitive data.
It's far from a perfect solution, but an even stricter system already works in law, medicine and civil engineering. It just moves us from the current Wild West back toward the middle. Getting there would take real consensus, though, and tech workers have historically resisted organizing, since many see themselves as individual high earners who don't need a union. Add lobbying from large corporations, and it's a long shot.