I say yes they'll never let him get the nomination again.
I'm not saying he will 100% be nominee if he runs, but how does the RNC or congressional leaders stop him? He's still loved among base voters, and they're the ones who elect their nominee. The party elite would never have allowed him to go anywhere in 2016 if there was a chance to stop him.
If Trump isn't the nominee, he either doesn't run for various possible reasons, or his cult just fades away with a majority of GOP voters. But there is no chance party elites stop him in smokefilled rooms. These times are long gone.
And you have become less Trumpish, SN? I'm surprised in a positive way.