Do we have most of regular users validating payments today? Not really, especially considering that most of the tx happen on exchanges, off the chain.
The way things are today and the way they need to be to ensure a censorship-resistant secure public ledger are not the same. Core is working toward that, security is first priority, then optimize performance after that.
> On-chain scaling is not sustainable. If you want to handle as many transaction as for example Visa, you would need 1 GB blocks every 10 minutes, which would make the whole blockchain heavily centralized because regular users won't be able to host full nodes to validate payments.