A usual complain about bitcoin is that some payment processors like Visa/Mastercard/Paypal can do several thousand transactions per second while bitcoin can only do 5-7
That is because those payment processors' transactions are all done in their own server, similar to an exchange. I believe bitcoin exchanges can also do several thousand transactions per second, or even millions like Nasdaq, given the right hardware setup. In fact huge amount of transactions happens daily on bitcoin exchanges
But transaction on blockchain is totally a different thing, its a true monetary transaction between different entities. Since with bitcoin you are your own bank, all the transactions on blockchain is essentially a transaction between banks. And we all know that banks do settlements between each other only once a day, not including weekend and holiday. From this point of view, bitcoin's transaction speed is already magnitudes faster than the fastest international bank settlement network (Swift, SEPA, etc...) on earth, it can do settlements between any different banks in 10 minutes, 24/7
So there is no reason to blame the bitcoin's transaction speed, it is already the fastest financial settlement network in world
An old article about bank settlement and bitcoin here
http://gendal.me/2013/11/24/a-simple-explanation-of-how-money-moves-around-the-banking-system/
