By the Wikipedia, the GMLRS stock is 50 000 missile, yarly capacity is 7000 .
if Ukraine has 10 HIMARs, and if each launch 3 salvo each every day then they use up 180 missile / day.
It takes 5 weeks to use up the whole yearly production of the USA, and takes 10 month to use up the whole GMLRS stock.
Means the bottleneck is not the HIMARS launchers, but the available missiles.
Doesn't make sense to destroy the launchers, the most important target is the supply chain.
If the available stock for Ukraine is 18000 (I doubt it... ) then destroying 200 decrease the capability by 1%.
Destroying 2000 missile more painfull for the USA than destroying 30 HIMARS.