Unless you live in Massachusetts and you are actually dealing with Romneycare and not just the ACA I don't see how you can blame Republicans who did literally everything in their power to stop it save for a handful of traitors to the party; and no the fact the Heritage foundation floated a similar idea in 1989 that went nowhere does not somehow make it GOP party plank in 2010.
As to propping up the insurance industry, you are nutz there too. Seriously if you think the Democratic party votes to pass healthcare reform that obliterated the private insurance industry would have been there, I have a bridge to sell you! Remember every state as a byzantine set of rules to more or less force every insurer to have some local presence and probably tax exposure there.
After that you have an entire chain middle men like brokers, resellers, re-insurers, who all have an intrest in private health insurance remaining the norm. If that isn't enough you also have a chain of hedge funds, mutual funds, bond funds and their respective ownerhsip that invests in these large mostly public private health insurers that also don't want to see change.
There are enough monied constituencies, that actually implementing single payer would be political suicide. I am serious we could have the president, senate, and house in DNC control and still no progress toward single payer would occur. Its one of those issues very much like abortion(at the national level). The pols are happy to talk about it but they don't want to actually deal with it legislatively, its better to use as a political football to stir up the base. If you are a Democrat and you need the optics of lots of people marching for social justice say some stuff about single payer. If you are republic and you need to ensure your base will show up on election day, tell them your opponent wants single payer.