"why no one talks about [all the other alternatives]"
Expanding the question because it's the same answer for all of them: The relatively steady exponential progress of transistors murdered all the competition. Nobody had any time to think about anything else when 18 months from now the transistors would be twice as fast and cheaper at the same time. It also meant a technology had to pretty much come out of the gate already better than transistors which had been through numerous doublings. It doesn't matter if you produced something that could hypothetically double every three months for ten years if it started out a hundred times slower and a thousand times more expensive than the transistors at release day. It couldn't survive long enough in the market to get funded long enough to develop that far.
It's only now that you can really get going on some alternative... and it still kind of sucks that even so you need to produce something out of the lab that beats transistors on some relevant metric right now if you want to get anywhere. Trillions of dollars of investment into transistors is hard for any tech to overcome, even if hypothetically in 10 years it could spank transistors somehow.