I consider the one which had no revenue last quarter besides registration fees to be dieing. (Wasn't asicminer)
The one which is a few months away from releasing an actual product may or may not do well but at least they have a source of revenue other than gamblers and registration fees.
Take a look at these nice graphs
http://www.btcalpha.com/mpex/stocks/s-mpoe/Those graphs show that registration fees aren't the primary source of cash flow, its the options market making activities.
Gambling is also very profitable industry, and BitBet seems to be holding its own; pulling in some high volume wagers over its history. The question remains whether that security and the options market making is enough to keep MPEx profitable in the long-run.
MPEx may be overvalued, but I don't see it as a scam by any means. Everything is very transparent, as well.
Q4 total profit = 938btc
Total profit from new users = 820btc
You are totally right that being overvalued does not make anything a scam. Having a business model which requires recruiting new gamblers/investors to pay 30btc registration fees as a major source of revenue is a scam.
Gambling is a very profitable industry as you said but I see no reason there can't be options/futures without a 30btc fee and the loads of bullshit that comes along with mpex.
Just for fun lets compare mpex.co to just-dice
Last year net profit: ~14,000btc vs 13,000btc
Total evaluation: 1,000,000btc vs 37,000btc
Profit split: 85% goes to owner 15% to investors vs 10% owner and 90% investors
Registration fees: 30btc vs 0btc
Blog fees: 0.01btc vs 0btc
PR fees: 12btc vs 0btc
Also bitbet doesn't seem to be holding its own. 150btc profit past year and 7200btc evaluation @ a whopping 2% apr. Not sure who buys this shit.