But, short of having a "how to subvert the speed of light" discussion, which would be exceedingly long (and probably unproductive!) -- you've given me an idea!
Yes, you are correct that the speed of electrical propagation is limited, and does limit things!
We're completely agreed there!
OK, so here's my idea!
F--- the electrical cable entirely!
So, we have Quantum computers, Quantum bits, and all sorts of research on how to compute things with them, all kinds of professors and papers and companies and venture capital all researching how to do Quantum Computation...
Well, I say F--- all of that! (In a polite, friendly, "yes your work is really genius and I acknowledge all of your brilliant contributions kind of way!").
Here's the grail!
The grail of Quantum is NOT Quantum Computation -- but rather Quantum Communication!
In other words, get rid of the damn electrical cable, and
figure out a way to do that communication with a pair of connected-at-a-distance Quantum bits; that is -- Quantum Communication!
In other words,
Quantum Communication -- should replace wires and busses of all sorts, serial, parallel, electrical, light, what-have-you.
That's the damn grail!... (pardon my language!)
Not Quantum Computing!!! (brilliant though it is, I am not trying to knock it in any way, far from, quite the opposite!)
Quantum Communication -- replacing wires and busses of all sorts, serial, parallel, electrical, light -- would be the Holy Grail -- of being able to build bigger computers (like imagine close-to-infinite RAM -- on one motherboard! Close-to-infinite RAM! Well, it would be off that motherboard... but Quantum Communication, if it were available, would, for all intensive purposes, make that RAM so connected, would have the net effect -- of physically existing on the motherboard, even though in actuality it would not be so!)
So, to answer your question...
YES, I DO SEE THE BOTTLENECK!
But... equal-and-oppositely...
Do you see my point?