You think, that traders really care about technically running any nodes? As long as centralized trading works, they will trade. Testnet4 can even be halted every 2016 blocks, and nobody cares (because then, all miners are forced to work with real ASIC difficulty for a single block).

There existed some CPU-mined altcoins, where validating the chain was harder, than mining the next block. And it didn't affect trading at all, and people shared already validated database in a "don't verify, trust" way.