Aren’t lasers extremely susceptible to weather conditions?
E.g. when it’s raining/snowing/cloudy, can the base station communicate with a satellite via laser?
While this experiment has demonstrated that it is possible to compensate for the turbulence of the air, there is no solution for the attenuation caused by bad weather.
It might be possible to use lasers between a base station and satellites only if the base station is located at high altitude in a dry place, like those typically chosen for astronomical observatories, so that the links will be blocked by bad weather only infrequently.
So I do not believe that there is even a remote chance of replacing most undersea cables.