No one has yet demonstrated the demand for such capacity. The majority of Bitcoin transactions are spam. (less then 10 cents) Prove to us that you can provide spam protection and low fees and maintain security and reliability and I'll support larger blocks. But you can't because you can't predict the future demand.
if a spammer was to make 3800 transactions at lets say 10cents. thats a cost of $380..
thats not really a deterrant for spammers.
how about 5700 sticking to normal traditional transactions with a maxblocksize buffer of blockstreams 2.85mb acceptable bloat.. and fees were 10 cents.
guess what.. thats $570..
which proves that doing normal transactions and increasing the real blocklimits means both more capacity per mb and more cost combined to fill the block, meaning slightly better deterrent.
even if we kept the fee's at 4cent.. blockstream 2.85mb =$152 bloat cost... and natural safe 2mb blocks= $160 or natural 2.85mb blocks=$228
u can increase the fee to whatever you want. but natural normal transactions with a maxblocksize increase is always going to allow more capacity and more combined cost to spam. than blockstreams roadmap
so lets say it another way..
lets say we want it to cost a spammer $1000 to abuse a block..(knowing its more about the total cost for a spammer to abuse a block, while also ensuring users dont pay much individually)
blockstreams roadmap = forcing the users fee to 26cents per tx
natural transactions same bloat = users pay 17.5cents
so blockstreams road map in any way you view it wont give capacity bu will force prices alot higher. while doing the natural capacity growth allows more capacity which in itself would end up costing a spammer more.. but without the physical data storage being any worse then blockstreams idea's