Hmm There are many good funds of hedge funds out there - no matter if the HFRX is investable, it is a good benchmark for FOHF performance. FOFs help you survive catastrophic losses in single hedge funds. If you invest in stocks you also don't just buy just 2 blue chips and pray either won't go bankrupt over the next 20 years. I doubt fees will come down in hedge funds simply because it's extremely expensive to run a fund - discretionary (expensive manpower) or quant (manpower, technology). Yes, the pay off is big if you manage billions but most funds do not. Also, there are few signs of hedge fund inflows ebbing off. We'll have have to see if the launching of 'intelligent' ETFs, commodity ETFs and short ETFs will change that over the long term.
Regarding Rogers, unfortunately we have no idea if he is making a killing or not because he doesn't publish his performance.
From the top of my head, he was allegedly long airline bonds, airline stocks (later in 2008), long JPY and CHF, short US brokers + FNM, long China and of course long his commodity indexes.
If I go through his list of publicized investments, I see half of these bets were good as of right now in 2008, the other half weren't as good. Hard to say if he made a killing.