Fair enough. I'm just a Technologist 3yr diploma. But I worked in technical support for an inverter manufacturer, among other various electrical QA type work. There's no doubt you are right, it's just that it's really hard to underestimate the advances in inverter technology. Ultimately rotating machines require maintenance that solid state devices do not. Sure inverters need replacing and optocouplers fail, IGBTs fail, etc. It comes down to rotating machines being bigger and needing more care and lubrication etc. Eventually the computerized electrical power is cheaper to distribute (distributed generation) and maintain.

That said, if you have cheap fuel, or enhanced geothermal, turbines are king. Even some exotic concentrated solar, molten salt storage with steam turbines makes sense,. But I can put 10 kW of solar PV on a building and basically set and forget. Not possible with turbines, everything has its place.

It's a really not a big problem. We can use inverters to inject anti-harmonics and provide reactive power support. Spinning turbines are find and dandy. But solar PV could do everything a turbine can do, and depending on what fuel is spinning the turbine, often for less cost. And very clean, modern inverters are getting to less than1% THD. I get it, spin make pure sine wave good. But you need a broader perspective on power quality.

I'll agree that ac distribution is still very much the way to go. DC has the low end of power usage, even some lighting is going to POE style now, and the high end HVDC transmission, but distribution will likely be AC for some time to come.