Yup. That would make Bitcoin either collapse or force the infrastructure into an increasingly small pool of operators thus changing completely the reason why some of us consider it to have strength. So, I agree that 'the future of bitcoin' does depend on this.
I normally qualify my statements of this nature as some form of a conjecture on my part, but since I am commenting on a statement which lacked this qualification I'll defer as well.
Back On-T, I've since Sept made over 20 sales through Coinbase with an average of over 5 figures each and none that I recall have exceeded the expected timings. Most beat the expectations.
Back Off-T, one of the risk factors that influence my draw-down planning is indeed the threat of mass adoption. Mass adoption or appearance of it will probably do great things for the price of BTC. At least for a while. But I am quite confident that it will change the nature of the solution to one which has limited appeal to me.