They can just not really worth the hassle/money. You can pull the cable up and change them out if you want.

Pulling a cable up, cutting a damaged part out of it and putting a new piece in is done all the time to fix damaged cables.

would the repeaters need to be replaced? if you are compressing the data differently or sending it faster or whatever, I'm not sure the repeaters care, they are just amplifying the signal, not decoding it and resending it.