It’s still a year out from election at this point. Right now he’s formally not running against Trump (properly he hasn’t even been nominated himself) so until the nominations are set it’s not helping anyone to effectively endorse a Trump nomination by running the campaign as though you already have a listed opponent. It’s a pretty well given, but treat it as if it’s not.

People have an exceptionally short attention span these days. Making a more generally economic policy framework as the message rather than speaking to specifics now allows them to leave the details until closer to the election when people have a better chance of taking note and remembering it for the next few weeks until they can vote and then go back to their regular lives.

At this point the population has become so polarized that all nuance is lost and people are just voting to keep the abomination that is the other site from utterly destroying the country.