All the Kelvin Enterprise sets were rebuilt from scratch for Star Trek Beyond, for that same reason (and I am so curious what The Picard Show will look like, since it's being filmed in LA and thus won't reuse Disco sets)And since DSC is shot in Toronto, it would be extremely difficult (that is to say, impossible) to actually move all the sets up there. Certainly more expensive than building new sets from scratch (or even going all-digital like BSG: Blood & Chrome).