> Gil Kalai can have his contrarian opinion on quantum computers. But we can have a much simpler argument against quantum computers. That they will remain infeasible for a long enough time for traditional computers to catch up to it.

IIUC and IIRC (both somewhat doubtful admittedly), Feynman argued - https://people.eecs.berkeley.edu/~christos/classics/Feynman.... - that only a quantum computer can perform a scalable simulation of quantum physics. Assuming that is correct, there is no option for "traditional computers" to catch up for all problems at least.