and that a switch could have happened anyway without governmental fiat
No the government want to sell off most of the spectrum that used to be occupied by analogue TV. I know, I was involved in lobbying our government (UK) and went to give them a demonstration and got very drunk on free Champagne as it went on into the night. So it's my fault! 
Like many inventions (telegraph, telephone, light bulb, etc) - there were a ton of people working in all areas, so it ultimately becomes difficult to say who was really "first" on anything.
What you mean to say is that a lot of Americans claim to have invented stuff that was made years before in Europe.
That would likely be mechanical-based;
Yes but it was colour TV was it not. It is just that because someone else came up with a different way of doing things doesn't mean he invented it. He just invented a different way of doing the same thing as was already invented.