yeah bro sometimes its a little of both.
as for RMRP it was legal and some others was because they couldnt turmn a profit because costs were to high and demand from them not enough.
like you said rocky mountain research products can still be contacted and items purchased via email and accept paypal or other.
i know there was some legal problems with co-owner and they are supposed to re-open as soon as thats cleared up.
as for some others i have heard they just simply screwed up, with wrong filters or cheap products that fail I.E filters.
others will tell who they still use im sure, so good luck and its just what i have seen.