The early 90's is also when they started showing less and less music and more shit like The Real World, Road Trip and Beavis & Butt-Head. Even when I was a kid and saw Nirvana's Unplugged set (arguably the best episode of Unplugged), the saying that "MTV doesn't have music videos" was already a popular joke.
Music Television doesn't necessarily have to be showing videos, but showing something at least tangentially related to music would be nice. MTV is now what every channel is: put whatever is required in front of the viewer to sell ads. All channels are the same shit now.
...at least through ninety-five they still ran music videos overnight and weekly themed shows (120 minutes, headbanger's ball, MTV raps) at specific timeslots, but by the mid-nineties music videos had been relegated to graveyard-shift filler as the network increasingly focused on conventional programming...
...fourteen years is a pretty fair assessment, methinks...