I think it isn't:

• First of all Hanlon's razor.
• It doesn't affect map users and rendering clients directly, as they display extracts, they don't use the main website directly.
• Power users also work with offline clients, e.g. I download the data, work on it offline, then upload it, so what I notice from this is sometimes the download or upload times out, but I just retry it and it works after a while. It's annoying, but not a big deal from my point of view.
• I think it mostly affects casual mappers, who add a lot of very important data, but by volume it's much smaller than the data contributed by the big mappers. There was a very good presentation about this in 2014: https://wiki.openstreetmap.org/wiki/SotM_2014_session:_The_Long_Tail_of_OpenStreetMap
• It affects mostly sysadmins, who will burn out.