Ahem.. not quite, although it might be..

Beta died for a couple of simple reasons that had little to do with marketing.

1) Licenseing fees, people say there's no evidence, but Sony is famous for this. they kill everything they make by being proprietary. I know the machines were more expensive at the time, and so were the tapes.

2) (the big one) 60 minute tapes. You can't record a movie on it. VHS, while an inferior format, could put a movie on a tape. Sony eventually fixed this, but too late.

3) Porn. the reasons are obscure (some say Sony not wanting it to be allowed, and some alluding to #2 above) but the fact is video store rentals, and adult video rentals drove the industry.

So really, not markteting, but more like market adoption, which can be driven by lots of reasons. (like the above)

I can't be sure why powermax died - I know I didn't ever see a canister made by anyone but coleman - was it a licensed proprietary technology that other manufactureres would have to pay for? Not sure. but if it was they might have "sony'ed" it.