Garbage wrestling worked for ECW because at the time, it was fresh, and you didn't see it everywhere.
Back when ECW was first gaining traction (95/96/97) you didn't see death matches in WCW or WWE. Guys hitting each other with barbwire baseball bats and slamming each other on tacks was attention grabbing.
But things have changed, and while those matches still have a place in wrestling, they aren't as exciting as they used to be. It's just been done too many times.
In fact, the fan's interest seems to have moved in the complete opposite direction. ROH is in a position very similar to ECW's, and it predominantly focuses on technical, clean, high spot wrestling.