As others have pointed out, LEO satellites solve the latency problem. Why then was this not done before? Because LEO satellites move. You can't use a fixed antenna for LEO; you have to track the satellite. This means you have to use a motorized antenna (cumbersome and expensive and generally impractical) or use a phased array antenna with no moving parts. Only recently has the technology for phased array antennas become cheap enough for average consumers. So the delay in fixing the problem was mostly the fault of antenna technology rather than satellite technology.

Postscript: Iridium is LEO and doesn't require a fancy antenna. How come? Iridium is designed for voice; throughput is a few kbits/second. That's way too slow for modern internet. For mbit/sec speeds, you need a higher signal-to-noise ratio and an omni antenna like Iridium's won't cut it. You have to track the satellite.