Russia needs to work with the private sector to buy and crew the ships, and there is only so many ships they can buy and lose before it's not worth the money or hassle for either Russia or their private partners.
It will be worth for Russia as long as the rust buckets they are using for the purpose are cheaper than cable repairs and knock-on effects from whatever downtime, and the uncertainty it brings to the West.
This assumes everyone agrees with sanctions. Various countries don’t and Russian exports are flowing.