So, instead of having one or two maintained projects that work super well, now we have hundreds or thousands of people half-assing it locally each time they need it? Doesn't sound efficient.

It might make sense to do this if there literally isn't an existing solution out there, but I think most would find that it's better to use an existing solution than to recreate the wheel every time there's a need. It's just less effort/time/money.

I have the same objection to forking open source projects; changes should be upstreamed when possible.