I have a friend who has been into RC for about 22 years. He's never tried a diesel. I put a Davis head on my 46 and we got it all set to go. He is quite impressed with the whole thing. He likes the smell! I think it lingers too long and must admit that I prefer glow fuel smell more.
My thought as to why people don't get into it, even if they've seen the benefits are 1) why change? 2) have to get all the extra stuff for it like different fuel line, a different type of fuel to store, different pump/bulb... and 3) no one else around to show them the ropes/get advise from.
JS