He used a different path that didn't require a 2/3rds majority, taking the risk of amendments such as over 16s than 18 eligible, and allowing EU residents to vote. Both failed and it's a standard election on that date.
Where Corbyn is stitching himself is by trying to be an honourable adjudicator. IE get the best deal he thinks he can then offer that Brexit deal versus not leaving. This is seen as a cop out by the hard leavers/remainers who want their way or the highway.
What isn't known is if the reasonable approach is a silent majority versus the shouters for one option or another.
Lib-Dems can't really expect to ignore the referendum and stay in with no further referendums without wide scale rioting.
Conservatives know that the deal agreed is full of holes and will still take years to work out with the threat of no deal not dead. Their best bet is to pretend that delivering Brexit is a completion rather than a starting process.
Already the conservatives are actively posting falsified videos via their official websites and refusing to apologise.
This is going to get nasty and personal.