Three years. People have been making issue tickets for three years about Bitcoin's block size.
"Core's" response was always to suggest an indirect fix to this by enabling SegWit.
>a masterpiece of engineering
Substantiate your claim.
>doubles the blocksize
Incorrect. 140% is the common number floated around.
>doubles the blocksize
140% block 'capacity' while using 400% more bandwidth. That is terribly inefficient.
>enables future efficiency gains
Substantiate your claims.
> and a laundry list of other improvements
Substantiate your claims.
>developed, tested, and released in _very_ short order.
Funny how Core halted development of Bitcoin for several years now up until now.
Now there is a frantic dash to get SegWit implemented as a fix to the block size issue even though it does not directly address it. What SegWit DOES directly affect though is the ability for Blockstream(Core) to roll out for-profit products that use Bitcoin as a settlement layer. This is the vision AXA[1] Strategic Investments and others have for Bitcoin and they are using their investments in Blockstream to make it happen.
[1] http://www.coindesk.com/investment-bank-axa-eyeing-bitcoin-f...
You forgot the most important counterargument. That they _did_ move extremely fast on scalability. They released a masterpiece of engineering, SegWit, which doubles the blocksize, improves efficiency, enables future efficiency gains, and a laundry list of other improvements ... all while being a softfork. And, IIRC, that was all developed, tested, and released in _very_ short order.