Well...In 2009, the Times reported the AMA was not enthralled with Obamacare...
http://mobile.nytimes.com/2009/06/11/us/politics/11health.html

In fact, the AMA even supports Mr. Trump's pick for SG, the Times reports, while remarking that even the AMA has reservations with aspects of Obamacare.
https://www.google.com/amp/mobile.nytimes.com/2016/12/26/us/tom-price-hhs-donald-trump-cabinet.amp.html?client=ms-android-verizon

I think rational people realize it needs some major adjustments.  For instance, 25% increases are not sustainable and there are other severe issues.  Why not wait to hear what the adjustments are before scuttling the concept?