Proven unjailbreakable phones are the wet dream of the mobile carrier industry - finally no piracy anymore and no way for users to get rid of bloatware.
The current status quo of the open-source community being able to make use of closed-source hardware, often producing viable devices where the vendors had hoped to provide something locked-down and near useless (e.g. openwrting routers, or that amazon button thing) is very nice, but does substantially draw wind out of the sails of open hardware initiatives: with companies able to subsidize the cost of hardware using other revenue streams, groups aiming to produce open-source hardware have to deal with not only per-unit costs being much higher due to smaller production runs but also the ability of many companies to sell hardware below reasonable prices due to charging for associated proprietary services.
If open hardware becomes the only hardware on which open software can run, its value proposition changes significantly for the better.