Bitcoin has clearly failed in an 'exchange' role as evidenced by still not needing to fiddle with the 7 tps transaction rate (1MB block size) and not being on a trajectory to need to do so any time soon. The reason for this is abundantly clear and I've been saying so for years: Bitcoin is simply not competitive in this role.
Bitcoin is not very competitive for buying coffee, but that isn't the only thing people do with money.
It's quite competitive for international remittance, black market activity, and micropayments. In some cases, bitcoin is the only method that works at all. Those markets alone are absolutely massive expansion territory for bitcoin.
The reason bitcoin hasn't hit the 1mb limit has little to do with the network itself, and much more to do with the shitty state of personal computing. Keeping high-value secrets was not what any of it was designed to do. Everything bitcoin needs for that has to be built now. A lot of progress has already been made. There's no reason it won't become easy enough for anyone to do.
However many transactions per second fit in a commodity internet connection, that's how many it will have, certainly much more than 7tps.
If you think bitcoin can succeed as a bank settlement network, you might as well sell now, because it's never going to work. The whole point of bitcoin is censorship resistance, do you really think banks and governments and payment processors see that as a valuable feature? They're the censors! If individuals don't have access to bitcoin, it will die, they're the only ones who could possibly care about it.