Obama tried. The Affordable Care Act barely passed. He had to make last-minute compromises with members of his own party to get it voted through at all.

It’s not a loophole in the sense that it’s an unintentional exploit. Everyone involved knew full-well what the point of that provision was. If Congress voted in something more stringent, their corporate donors (e.g., Walmart) would have been pissed. That’s a deal-breaker for most Congress-critters.