Not really a lack of support from the aftermarket. It may not have the following of a remmy buy still solid aftermarket. Timney, rifle basix , jard make triggers. Stocks , boyd's and mcmillian atleast have production stocks then some others have there spec'ed stocks from boyds and several custom fine wood makers do rugers. . Mine is going on 16 years old now. What other aftermarkets is needed. barrels sure ain't a issue. Only reason you don't see them at matchs has more to do with the owners choices of useing push feed actions than the ruger control feed action. It is a control feed with the mkII and for the same reason you see no rugers you see few mausers or winny full custom rifles for match play they need to feed from a magizine to function.
The man the built mine was an old school mauser smith and only because of that skill did he do mine and still with some whinning. He had a change of heart after the work saying it was easier than a old mauser. But he did have to build some tooling for it.
My 15 year old custom Ruger , Boyds JR stock bedded and blocked , timney 1 1/2lb trigger and krieger 27" #7 profile 7mm RM- Good LR shooter.