You can't do the caltrop trick at 50 locations for weeks on end.
The thing about lasers is they use a very narrow slice of wavelengths. Environmental light like sunlight has very little power within that slice, so its easy for the LIDAR to see its own laser. But that makes it really easy to jam. You could probably build a jammer today for a few hundred dollars, which means that in the future every disaffected monkeywrencher will do it. Ergo the approach is not suitable for the mass market.
The thing about lasers is they use a very narrow slice of wavelengths. Environmental light like sunlight has very little power within that slice, so its easy for the LIDAR to see its own laser. But that makes it really easy to jam. You could probably build a jammer today for a few hundred dollars, which means that in the future every disaffected monkeywrencher will do it. Ergo the approach is not suitable for the mass market.