The French government put a bit of money on the table to help researchers fulfil their open science requirements for government and EU grants, and funded the HAL repository ( https://hal.science/ ). It’s much smaller than arXiv, but it exists. In other countries like the UK there are clusters of smaller repositories as well, but it’s not as well centralised.

It’s so important, in fact, that there should be more than one such institution.

People keep falling into the same trap. They love monopolies, then are shocked when those monopolies jerk them around.

it just hosts pdfs, no?