FB,
If you choose not to believe stated US Government policy there is not much I can do to change your mind.
However, if the GNSS (not just GPS) signal is completely lost, for whatever reason, aircraft will not fall out of the sky. The laws of physics will still apply to keep them airborne, there will be a back up network of radio navaids by which to navigate and although there may be no surveillance in some ADS-B only areas procedural separation standards will still apply. At worst there will be some delays outside of the remaining SSR/PSR network.
I think you are overstating the risk here. Remember Risk=Probability x Consequence. The probability is low and there are measures in place to mitigate the consequence.