There are always containers coming in, and Euro stock shows no real sign of drying up any time soon. Some titles domestically are a bit harder to obtain but anyone willing to pay a fair market price usually has no trouble locating just about any specific title. That is what I inferred by supply doesn't really change.

I've been collecting pinballs for a while, have personally imported containers and have heard all the huckster talk for years about pinball machine supply being exhausted (Bumper's infamous spiel from 2006 - last lot of European machines found hidden in a cave in the Swiss Alps springs immediately to mind, second only to pinball machines are a guaranteed investment).