Hasn't it ever struck people how utterly pants much of our power generating tech is after all these years? Take batteries as a good example, heck, those 'vintage' rockets we still use to send payloads into orbit too.
Tesla is a good one to mention and was a genius who sadly got screwed over in the end. Look into history (not all the mainstream junk) and see who would have been set to lose out massively by the development and release of energy devices that could basically power a home, industry or transport for basically nothing (or very little) and then you'll see why we're still using this outdated rubbish.
Afraid to break it to some of you still in la-la land, but these devices have and do exist but are repressed. The lucky inventors just get a warning or money to shut up and go away, the not so lucky ones, well you can figure that one out - those who currently benefit will do anything to maintain their positions of power and wealth, let's put it that way.
TLDR: You're right! Believe everything the mainstream science and media tell you - nothing to see here.
. Because of course the evil Oil Companies would rather carry on spending billions looking for and extracting oil/gas to sell when they could just create the energy for free to sell if they only hired/kidnapped one of these genius free energy machine inventors. Yeah, makes perfect sense that they'd pass up on the free energy and carry on drilling. OK.
... that's what i think of whenever i see the words tesla coil