When a problem is partisan, you have ~50% of people on your side, and ~50% deeply opposed. When you're non-partisan, you're on your own. Instead of facing bitter opposition, you're facing a vast wall of apathy.

It's hard to find anything that's so overwhelmingly popular that people will be on your side just on the merits of the proposition. If it costs any money, somebody will be opposed. If it benefits somebody more than others, somebody will be opposed -- even if it's a benefit to them, but a smaller benefit than somebody else. Some will oppose it just because they dislike you personally.

And because of partisanship, they have allies, who may be apathetic but will support them just because they care. Now you've got ~0% of people on your side and ~50% of people bitterly opposed.

Being non-partisan is a lonely, frustrating business. You don't see much of it because it has a very poor track record.

It would be great if we could ditch all of our existing alliances. But new ones would form almost immediately, because you need them to get anything done. The resulting web of connections might be different, but the level of partisanship will be similar.