Obama might have tried to do it, but there's more to lawmaking than just writing it - there's also implementing it, which Obama most certainly did not do. And as a member of the Executive Branch, that's kind of his job....

Or are you implying everyone just ignored it for 12 years?

Also, Trump's order is significantly larger than what's in the ACA, and Trump actually implemented his order.

You can give Obama credit for trying, but Trump gets credit for actually doing it, and for doing it much better than Obama.