The constitution only requires a simple majority of the senate to pass a bill, and there is a tiebreaking vote. The 60 vote threshold is only because of a self-imposed extra-constitutional rule, one which can be abolished with a simple majority vote via the "nuclear option" [0]

Effective lawmaking is not some impossible feat under our current system, it was commonplace until very recently. All that has changed is that we've grown complacent and now continue to vote for those who refuse to do their jobs.

[0] https://en.wikipedia.org/wiki/Nuclear_option