This is a feature that would be used by 0.00000001% of Google's userbase. It would have the effect of shutting up that tiny subset of Google's users while allowing Google's result to continue to degrade silently. Google may not agree that it's in their long-term interests to hide a problem that may eventually make them competitively vulnerable.
It's also possible that the fast path of "simple search" -> "standard SERP" is so optimized that serving that 0.00000001% of users might involve a headache disproportionate to the payoff.
It's also possible that the fast path of "simple search" -> "standard SERP" is so optimized that serving that 0.00000001% of users might involve a headache disproportionate to the payoff.