What improvement came first?

Its true. Like the other day we were all at Mike Lavigne's. Best room acoustics I have ever heard, by far. For a while there I thought it was his fine system. But then we got a call on speakerphone and dang if that wasn't the finest audio I ever heard. So whatever you do, forget the system. Build a room. Then all you need is a speaker phone. Bose Wave at the most, stick a fork in it, done. 

So in my thinking, speakers advanced ahead of amps.  It was only once speakers became good enough, that the more subtle differences could be heard. But is that correct? What improves came before other ones? Did tone arms need to improve ahead of more advanced cartridges? If so, then improvements of one part can totally depend on advancement of another part first.

Not even. It doesn't matter what you have, a change anywhere is the same. There's no such thing as system matching, synergy, or weak link. Everything is what it is, and will be heard for what it is, regardless. 

You seem to think Linn couldn't show how important the turntable is except that speakers had gotten better first. When in fact the turntable he made was so much better than the speakers of the day those exact same turntables are used and still sound outstanding, we can see clearly the Linn was superior in caliber to the speakers of the day, proving that way back then they were the "strong link" if you want to call it that. 


Which blows out your thesis, since Linn was able to develop that turntable in spite of there being no speakers (or amps, or interconnects, or speaker cables, or power cords) that were up to the level of the Linn at the time it came out.

This is all able to happen only because you can hear all these little improvements made anywhere in the system even if the downstream gear is lower quality. You just have to listen for them. But they are there.