And, as they don't, it's purely hypothetical.
If the Senate cared about passing relatively progressive bills, or advancing President Obama's agenda, there's a pretty obvious way to break through the Republican Party's childish obstructionism. Give them a choice of two bills:
A reasonable bill addressing the issue; and
A compromise bill that, should the other bill not pass, will be passed into law through reconciliation.
The problem is, that won't get them the pork they want. And how do you get fifty-one votes for a progressive bill if the trough is empty?
Similarly, the Dems could pull the same sort of ploy the Republicans used in relation to the filibuster - "Join us in doing X or we'll exercise 'the nuclear option'" - Doing X in this case could be as simple as "join us in a debate over filibuster reform that will end gridlock - or, via the (your) nuclear option, we'll just do away with the entire thing."
That's an even bigger problem. The powers that be - the Senate leaders - are able to insert huge amounts of pork into bills in the name of 'getting sixty votes', and with that supermajority requirement a Senator like Lieberman can assure himself of millions of dollars by insisting that progressive elements (supported by 59 of his colleages) be stripped, and a senator like Ben Nelson can similarly block a bill unless he is granted a windfall for his state.
Doing away with the filibuster would mean that much less pork, and so many fewer special interest dollars flowing directly and indirectly into their pockets. Unthinkable!