Hmm. OK. Well, having a background in Electronics I think I can address a couple of the issues you brought up so let’s look at them, right?
First of all, as long as you have a voltage differential of at least 0.7 Volts, you can build a step-up regulator to bring the voltage up to a more usable level. Both step-up transformers and step-up switching regulators have been around for a long time, and I am given to understand that companies like Linear Technologies, ST Microelectronics, and National Semiconductor (just to name a few) have small devices that are about the size of a standard TO-220 package, with some additional legs for any necessary additional components.
Secondly, there are several electronic switching methods currently out there that can perform switching functions quite well, so the requirement of being connected to the mains at all times is not really a “requirement” at all. I even have switches in RF transceivers that can switch between receiving a signal to transmitting on that acts in fractions of a microsecond, so not much worry there either.
Also, please take note that with very few exceptions, Solar / Photovoltaic devices rely upon the existence of solar energy to operate, and store the energy generated in some manner of battery device(s) for use during the part of the 24-hour Day/Night cycle when solar power is not available.
Or they simply cease operating at night, which might not be a problem for utility companies but commercial enterprises and personal installations do not, as a rule, find that to be an acceptable position to maintain.
Just a few thoughts to peruse.
I think they will eventually iron out all difficulties, it just takes time.