If you make an assumption of ever-increasing technological means, it will *definitely* happen. The only question is "how long before it does?".
It won't happen. You obviously have little knowledge on the scaling of large systems (distributed vs centralized vs decentralized). I'm not saying that we will never be able to process a lot of transactions; I'm saying that we will never be able to process more than a centralized and well expanded system like Visa (on chain transactions).
I disagree on the "it won't happen" part, because, well...maths... It's not a matter of if. Only a matter of when. It could be 30 years or 60 years, but at some point even 1GB or 1TB blocks will be peanuts for the standards that exist in future time-space coordinates.
I agree on the "we will never be able to process more than a centralized...", because, well.... p2p inefficiency.