https://medium.com/@WhalePanda/the-extended-extension-block-story-5bc3d888bddeI recall being told by a BU supporter here that the extension block proposal was incompatible with covert ASICBOOST. The article in the link indicates this was a late change after the ASICBOOST scandal broke. It would have been a non-starter otherwise.
As the article notes, going with extension blocks would involve more delays on the order of a year or more, while Bitmain keeps racking up profits while they are able to keep using covert ASICBOOST. This is all about delaying Segwit, which is ready today, while additional miners are driven out of business and Bitmain consolidates its power. Note also the pathetic unwillingness to admit SW provides a TX capacity increase as well.
I note that the extension block proposal came from Purse - a company whose service I like, but Roger Ver of BU lists it in his portfolio (
https://rogerver.com/). So this is not coming from a neutral party.
