For a few weeks I've been reading the conversations about block sizes and the experiments being done on the subject with larger blocks.

On the day with the most transactions, the Bitcoin block chain averages about 73 transactions per minute. I kept wondering what blocksize we'd need for handling 100,000 transactions per minute, and estimated that roughly we'd need a blocksize of about 1300x times larger than what we have now, so bigger than 1Gb block... but seeing the numbers Alipay gets to handle just in China make me wonder how scalable is Bitcoin if it were to truly compete with worldwide financial services.

If you were to include double the number Alipay can handle, you'd be shooting about 6 million transactions per minute, or roughly 60 million transactions per block.

If you average every transaction around 250 bytes, then you'd need ~15 Gigabytes per block to be broadcast and hashed by all the full nodes every 10 minutes, eating good 2Tb of storage daily... do miners have enough bandwidth and CPU power to handle this? 

are my scalability concerns absurd?