I really don't want to just bang the 'exponential progress' drum but you're probably not accounting for it enough with these examples. The ubiquity of computers

I really don't want to just bang the 'exponential progress' drum but you're probably not accounting for it enough with these examples. The ubiquity of computers and phones isn't just a consequence of the theory underpinning them being developed into industrial applications, but of the myriad related ways that industrial engineering, society, and the economy had to develop to support and necessitate their existence. Those last two were indeed probably the most viscous factors in the way of technological progress, up to this point, more so than the science and engineering challenges involved, though they are clearly all interlinked. Now, however, it's probably the case that the scientific and engineering challenges are the biggest hurdles - we already have the society and economy hungry for more computing power. Assuming the necessary breakthroughs can be made to make quantum computing a reality in the next 10-15 years (obviously a big assumption, and not intending at all to sweep that aside, it could take decades, but just let's make that assumption) it's not at all difficult to see how it could rapidly find its way into production and then ubiquitous industrial application, and 20 years then does not sound outlandish at all.