OP, care to share the ballpark figure for a Binance DEX? It's surely cheaper now that the path's been struck.
The question is whether it is still worth opening a centralized exchange. Many exchanges have recently closed, as they can no longer be operated profitably. In addition, centralized exchanges are increasingly required to execute KYC and AML, which requires additional resources and generates costs. A exchange has to grow big fast , otherwise it has no chance to survive.
I think, if a good business model can somehow balance regulatory compliance and privacy, take the best of the old world and fix it up with responsible monitoring aka Japanese model, it can certainly work well. I'm a big fan of DEXs and still want to see them succeed (and I believe they will) but for as long as people actually still prefer custodial services (and they do, actually), a well-managed CEX can still be very profitable. Binance proves this.