Visa, in 2012, in the US alone, handled 47 billion debit card transactions.

https://www.creditcards.com/credit-card-news/debit-card-statistics-1276.php

Let's round up to 50 billion; it is almost certainly higher than that by now, but we are going to be real fucking generous to BCH in this post.

Let's assume that the absolute fucking peak of Bitcoin is this number; pretty sad if you really think about it, but fuck it, let's roll with it.

Now, let's be ridiculously fucking generous, and say you can get 20k transactions on an 8mb block with no segwit. You need 2.5 million blocks to service that number; 20 terabytes.

You also need to handle 285 blocks an hour if you don't want to increase block size further, by the way.

Increasing the block size is not a solution. At. Fucking. All.

And block chain size isn't the only issue. It's just one part. And even that is totally fucked.