Bitcoin runs about 60K transactions per day which is less than one transaction per second. Even allowing for the fact that transaction flow is not constant throughout the day this is not even close to being a serious issue.
One would hope that 60k transactions a day is not the apex.
Again, reading comprehension is important. The question was about scaling to the current rate of Bitcoin transactions, which is to say something that a comparable system has been demonstrated to be able to handle, thus a realistic basis for comparison. Scaling Visa rates or anything close to that has not been demonstrated by any comparable system.