Timing matters. If the labs succeed here they will likely do so by paying off Trump, who doesn't care.

In 2028 a maximalist case could then be made to nationalize them.

The government actually running them isn't great, but no one ever gets 100% of they want in politics. It's about trafeoffs. If the labs use the current government to pull up the ladder, then the voters should vote for a government to swing hard to punish them.

In theory the threat of this should also act as a deterrent.

There's nothing weird about this at all. Politics is all about push and pull, carrot and stick. No one has permanent influence over affairs, and no one ever gets 100% of what they want. Yet it is entirely coherent to advocate for something like nationalization or take your pick of threat to private capital if they essentially cheat by pulling up the ladder because they've suddenly decided they don't want to compete.