Or just extend the logic to materiel instead of personnel, like Ukraine did with the airbase attacks earlier this year: for the price of a few dozen < $1k drones, you can eliminate $50M-$150M+ aircraft? The asymmetry is insane.
There's also nothing that practically stops those same tactics from being aimed at other soft infrastructure targets: electrical substations, telco facilities, water treatment facilities... the nightmare scenario is taking down transmission lines and switching stations outside, say, a large nuclear power plant during a heat wave. The nuke itself is hardened, obviously, but who cares if it can't transmit the power it's generating to the people that need it?
It also took 18 months to insert the people, set up the shell company, smuggle materials, manufacture, etc. It also had the advantage of surprise - the first such attack at such a distance from the front line. Is it unlikely such an attack will be replicated, just as a box-cutter hijack of 747s attack against buildings will not succeed again.
There's also nothing that practically stops those same tactics from being aimed at other soft infrastructure targets: electrical substations, telco facilities, water treatment facilities... the nightmare scenario is taking down transmission lines and switching stations outside, say, a large nuclear power plant during a heat wave. The nuke itself is hardened, obviously, but who cares if it can't transmit the power it's generating to the people that need it?