But still, lets run through a hypothetical with the farm bill, which is basically all welfare of varying stripes. Among others, the
farm bill has two components:
1) Corn bioethanol subsidies - This would never be approved alone because the rationale is stupid and it is basically a wealth transfer to a handful of corn-growing states.
2) SNAP - We also have been funding SNAP in this package. If split out on its own, this doesn't make it to 60 votes either because Republicans (including their senators) have the mistaken impression that SNAP is all cash handouts to urban PoC.
I'm not sure if any single part of the farm bill is actually popular enough to pass on its own. The alternative to the bloated farm bill isn't a subset of the policies passed in single-issue legislation. It's nothing passing. Libertarians would find that preferable, but I'm less sure.