Not going to happen. The only type of grid stabilization that miners can provide is when electricity prices go negative. While that does happen, it's very rare and the total amount of energy involved in those situations is small. Installing miners just for those rare cases will never be profitable due to much higher capital costs than other ways of absorbing excess energy (eg dumping it into load resistors).

Also, the instances where overproduction happens are likely to be fixed in the future with better supply-side regulation of renewable power.