Yes, I seriously question whether their business in the whole has doubled in that year. Ie twice the revenue and profit, etc.
It's just more in favor now than it was a year ago in investor sentiment
A better question would be whether the expected value of all future cash flows has doubled. Evidently, a lot of people seem to think so. (Whether these people are rational is whole another question)
It's rather than all other investments are worse, not that this one is real.
If there is a finite limit of "investable assets", then the relationship between those assets prices is not necessarily driven solely by sentiment in favor of Apple.
It could be that almost all other assets have seen their expected future cash flows fall while Apple's has slightly risen.
It could be that people's decision is not driven by future cash flows, but some other metric or feeling.
Have Tesla's expected future cash flows increased by 8.6X in the past 12 months? It's stock has gone from $220/share to $1,900/share.
That said said, if Apple bought them for accelerating their self-driving car development, the historical profit margins are irrelevant. The the valuation would still be all about the future opportunities and future cash flows. This relative to other opportunities in the market, as other commenters rightly point out.
In real dollars, or nominal dollars?