2) I can see x64 hardware on bit costlier machines. And,i can see arm64 on cheaper machines. On general computing devices, as price increases ,you get to see less arm64 hardwares.

I had low cost laptop with AMD processor. It compiled faster and handled load better than Rasp. Pi. of comparable hardware(similar specs not exact specs).

Rasp. Pi was ofc cheaper than AMD laptop.(about 0.4x of AMD laptop).

I don't think AMD laptop consumed lot of power than arm64 Rasp. Pi. arm64 being lower in cost consuming lower energy ,you can feel that arm64 is better than x64 in perf/dollar or perf/watt but reality is that there is no comparable hardware of both architecture in respective product range and difference is not that apparent when it comes to arm64. Also my AMD laptop compiled,cross compiled,handled large load much better than arm64 hardware of comparable specs.

1) Yes, power saving is desirable feature. I can't see arm64 workstations around. So,if you need performant hardwares,i think that x64/ppc64 becomes inevitable.

3) Definitely a bummer , still unresolved. Let's see how it goes. x64 has benefit in this point.