Excellent, *EXCELLENT* point. It's called, switch the DC on and off, step it up, and wow... you have the required VCC. We used to do this years ago for displays using nothing more than an OP amp as an oscillator at an AF frequency, and use that as the basis for our crude switching supply. Also, what's up with one modulated stage feeding another, then feeding another and another? If you are going that far, why not just amplify the carrier or exciter, apply AF at the last stage, and create class D AM? Efficient, and it's simple using modern devices. A lot of the broadcast industry is doing it, and has been for years.
Now, for other modes, where linear stages are needed throughout you of course couldn't do this, but once again, the problem of low impedance, stable, bias supplies for BJTs is gone with modern devices, and is so much more simple. Simple voltage dividers work here.
Anyway, before we get knocked for getting off topic, I wanted to chime in after seeing your last post because to me, it just made perfect sense.