Address reuse is currently being prevented by a list of all addresses which have already sent a transaction (previousEpochsSpentAddresses.txt) and this list is checked by the full node (or remote node) before sending a transaction. This list contains roughly 650,000 addresses as of today and is 51MB in size.
If my understanding is correct, every single transaction will generate an additional entry in this list since the sender address shouldn't be reused any more. So if IOTA would process 1 Million transactions per day, this list would grow around 75MB a day, is this correct? Why are there only 650,000 entries right now and why it grew just by about 260,000 entries within the last 6 months from the initial commit? This would imply an average growth rate of 1,500 newly used addresses per day which have not been used before. Are these all correctly used transactions or is there any additional selection of addresses which land on this list?