Bitcoin can surely scale. It can be larger than Visa in less than 5 years, if there's enough demand.
130 million transactions per day
Good luck with that.
In simple terms, what exactly is the issue assuming the max size can be increased as necessary?
The blockchain right now grows about 30 MB per day. That is at a daily volume of 60000 transactions.
Scaling up to Visa's level of transactions would translate to blockchain growth of 65 GB per day.
Median download speed for the US is 3 MB/sec. Downloading a 65GB file at that speed takes about 36 hours.
This argument is akin to saying that we will never be able to watch movies on the internet when we were running dial up. Both bitcoins pruning ability and other technology will be upgraded (we are still in beta, remember) and the internet's pipes are going to get MUCH larger (As soon as google decides to roll out their internet to the rest of the US/world). Additionally, your entire argument hinges on decentralization by people, not corporate entities, which in a worst case scenario would be entirely acceptable to keep the blockchain going strong.