With a larger block there's also a greater bandwidth required.

Fortunately, whether something does or does not hold merit in your eyes is nothing that matters with bitcoin. What matters is whether or not your transaction is valid, according to my node. So even if you somehow persuaded the lead / maintainer to merge your pull request for bigger blocks and that was what was released, my node will reject those blocks (as I will not update to that flawed release). If there are many of us who do not update, and we run "economic nodes" (i.e., significant amounts of economic activity), then the miners are going to have to decide whether they really want to go with the big blocks side (and possibly end up with coins that are unspendable due to little demand), or do they ignore the big blocks side entirely, even if that's what Core devs had released??