Try convincing the CTO that this panoply of smaller players will be around for 5yrs or worth the effort migrating to.

I'm at a much smaller outfit now so we have more freedom but I'd dread to think the arguments I would've had at the 4000+ employee companies I was at before.

In that same period the big players have only gotten bigger and the "Mittelstand" in tech has been practically dying. Replaced by the flood of VC startups that are far too obsessed with "growth" to care about reliability and stability.

(Note that "is this company financially viable in the long term future" is an important part of stability. Doesn't matter how rock solid the software is if the startup's bankrupt by the end of next year.)