Trump’s continual pandering to white males (especially white males without college degrees) isn’t about getting them “locked in”. It’s about Trump being in this for the adulation he continually gets from many people in this particular demo, so of course, they’re the ones he wants to spend his time with. After all, the great ego needs to be fed.
It’s also for this reason that Trump is going to spend precious campaign time in solid red states, where he’s going to get the state no matter what he does. He’d much rather spend his time among established friends instead of expending any effort making new ones.
And this is just fine — for Democrats.