First of all, there's no thing such as full/absolute decentralization.
I'm actually in fact surprised that TxTenna hasn't met a backlash from the governments (although I think the fact that GoTenna doesn't maintain their products anymore could be taken as an indirect backlash...)
Maybe because it's not popular? For comparison, their github repository (
https://github.com/MuleTools/txTenna) only have 71 stars, while blockstream satellite (
https://github.com/Blockstream/satellite) have 822 stars.