I agree that market forces will be the deciding factor, not governmental. Remember that Radium bulbs were not reefing bulbs until about 1999/2000 ish and they were general purpose and just happened to look very good for our purposes. I have no doubt that these bulbs have declined for general purpose use in shopping malls, restaurants and other places in Stuttgart, Cologne, Prague or where ever... even if hobby use was still strong. That might make sense for a company to stop producing since the aquarium trade was a rounding error for them. However, this can still be profitable for a reefing company to take over.
The way that it was explained to me is that the cost to make bulbs has been sunk and paid for many decades ago. There can be differences in formulas that go into the emitter to change spectrum and stuff. It costs nothing to keep a machine around to make glass tubes and stuff. Heck, people still make VHOs since the things needed to do it have been paid for since before some of us were born. Think of this like the cost of making a carburetor... not many cars use them anymore, but you can still get new ones since the dies and machines were perfected a long time ago and it doesn't cost much to fire up every so often and make a few thousand... and then let push the stuff into the corner for a while until you need it again.
Vacuum tubes, carburetors, bias ply tires... all sunk costs that can stick around with very low demand. Some things can make resurgences like Vinyl (not comparing reefing lights to vinyl, BTW). Believe it or not, many people still think that MH are the ultimate in performance (few should argue this even if other factors keep somebody from using them) and ultimate things in any hobby stick around... generally.
Again, I am not saying that any of these bulbs will be around for years to come, but I would expect massive hobby exits to be from poorly run businesses, economic downturns and retirements.
