Not the real problem anyway
It's hard for me to imagine that these calls from legitimate businesses represent even the tiniest fraction of nuisance calls. Perhaps it's different in the UK, but in the US I haven't gotten a spam phone call from a legitimate business of any kind in at least a decade. It's been years since even a scam call featured an actual human on the other end. Robocalls from spoofed numbers, presumably overseas, trying to scam me (or an alternate-universe me who understands Mandarin, at any rate) average a dozen a week. But they are criminals anyway so they won't bother to check TPS/DNC/whatever lists because the penalty for the unwanted call is nothing compared with the penalty they'd get for the criminal enterprise itself, in the extremely unlikely event they ever get caught and/or extradited. This really seems like the sort of offence no one would commit, not only for the reasons @Lee D describes but also because the only people they can punish are the ones they can find, and the ones they can find are exactly the ones with an incentive not to do it.