You're confusing present danger with future danger - in the future, AI and the supporting hardware may be ubiquitous (fat client scenario) - you can observe yourself presentation of laptops/machines with large RAM and high bandwidth.
Additionally, there at different doom scenarios (thin client scenario) - it's possible that AIs centralized but sufficiently entrenched in society, can't be shut down without considerable harm.
Meanwhile we're rationing ram sticks like we rationed potatoes during ww2 and a gaming gpu costs 2 to 10 months of rent, I think we'll see these fat clients coming....
i don't think anyone knows how this will play out - everyone is just anthropomorphizing, extrapolating etc... and i think it's nonsense - not because i don't believe that is the correct thing to do but because i believe this won't stop anyone from moving forward. This is what humans do, they move forward and cause others to move forward or lose out.
If someone has a fat client powerful enough to do all that, is a kill switch going to work? If we assume there's bad actors using the tech, why wouldn't there be bad actors building it?
But if we don't think about any of this, hearing an expert say "we need a kill switch" sure makes our current AI seem super powerful and exciting, doesn't it?