I'm sure beta has been around for a while, but a lot of manufacturers will not upgrade to Android L. Why? Money is to be made. A Toshiba Excite I have is stuck on ICS, LG phone on ICS, and an HTC phone on Gingerbread. All of these devices have the power to run L, but what's in it for the manufacturer to send an OTA or downloadable update? Nada. Go out and buy a new device.
Right now I'm on Kitkat 4.4.1 (which doesn't even have a 4.4.4 OTA update) on one Sony Flagship and the new flagship just hit the market with 4.4.4. Are any of these going to get an L OTA update? I doubt it. Going to have to get a different phone when they start shipping L on board. Too soon to go out an upgrade though, or you may get stuck with "crap" when the manufacturer doesn't want to upgrade it (example, HTC with a bad Gingerbread version).