There are plenty of talented drivers racing 17.5/13.5 that are capable of competing with a modified motor. The problem is that instead of racing for the win like they are in the blinky classes, they are racing simply to make the main.
They do not like this nor do their sponsors. It is as much a top class thing as it is a modified/speed thing. Even if you were to slow modified to 13.5 speeds or make 13.5 the top class, the same guys are going to win, the same guys are going to be fighting to make the main and will instead drop down a class. I am sure that the IIC 13.5 winner the past few years has been a pro modified class driver.
In my opinion the problem is just as much about competitiveness as it is about speed.