I do understand that the president doesn't have the power to fulfill every promise they make while running since they don't control congress so I give slack to Trump in some areas.
I think Trump has done a number of good things and a number of bad things.
The part about the ACA is that his administration signed onto the lawsuit attempting to strike down the ACA. If you strike down the ACA without something to put in its place the preexisting coverage will cease to exist. That is the crux of the matter as I understand the current lawsuit.
Insurance for pre-existing coverage is a misnomer. It cannot exist by definition.
Insurance is something you pay up front and then claim benefits from if you experience a covered event/situation/illness.
Saying insurance covers pre-existing illnesses is crazy. It would be like going up to the craps table, watching the shooter roll a 12, then putting down a table limit bet on the "field". That's not a bet. That's a sure thing, just like asking an insurance company to provide benefits for an illness you already know you have.
What needs to happen is there needs to be a premium adjustment for pre-existing illnesses. Basically, you'll pay more for benefit coverage, but it'll give you coverage for newly diagnosed illnesses and prescriptions, tests, etc. You won't be rejected based on the pre-existing because you'll be paying extra for the services.
Some companies already offered insurance coverage that excluded the pre-existing illness from benefits under that policy but with a rider you can purchase to provide services for that illness. So it's not like ACA invented pre-existing illness coverage. ACA simply made everybody pay more so men could help pay for OBGYN and women could help pay for prostate exams. This is why most of the healthy young people ACA counted on to subsidize the older, sicker patients with their increased premiums opted out. It was cheaper to pay the annual tax/penalty than struggle with premium payments.
If you can't afford the additional costs, there will always be subsidies under Medicare and Medicaid. But it at least shifts the burden of increased premium costs to the people needing the services and not every single person under that plan.
I would love to drive my whole life without insurance and be able to call up the day after I hit someone to sign up and file a claim. Pre-existing damage coverage. Bwahahahaha!!!