I think you’re taking it too literally. In the movie “Pumping Iron,” Serge Nubret says to Arnold Schwarzenneger at the 1975 Mr. Universe competition, “You are unbeatable!”
Did he really mean forever? Just that competition? Until Arnold retired? I think the expression “unbeatable” always means “Under the current circumstances, roughly now-ish, for the foreseeable future, &c.” If you take it literally, there would be no use for the word.
Saying “Arnold is Unbeatable” in 1975 meant that the current crop of body builders couldn’t beat him, that either he would grow old, or retire (which he did, and then un-retire to win again), or some new young phenom would come out of nowhere.
Saying “IBM 370 is unbeatable” in 1979 meant simply that nothing at that time would beat it, that only time or the unforeseeable would unseat it, which is what happened.
The word is always used with an implied context, yes, but that context is never just 'the present' with all circumstances staying as they are.
To call something 'unbeatable' means that there are still variables that can come into play in the contest, but they don't even matter. The victor is already decided even allowing for the most extreme probabilities.
For many or most of the items in the list you were replying to, the contest was not over when the crown was lost.
The OPs list was intended to show that many companies lost their tremendous advantages in a variety of ways, that the variables are such that the iPad shouldn't be labeled as unbeatable.
And of course, no one really believes the iPad is unbeatable in any meaningful sense. It's just hyperbole for being in a dominant position.
To say that something is unable to be beaten is intrinsically a claim about the future.
Really? Everything I know about philosophy, science, and traditional knowledge points me towards the notion that everything is transient.
Anyone who states or receives the message that "something is unbeatable" with an implied "indefinitely" is naive or has been lured into wishful thinking.
This article was focused on the business landscape and Apple's competitors. Saying that some new technology may emerge in the next decade or two to unseat it is missing the point. If the Ipad turns out to be unbeatable for the next decade or two, some very big companies will be going out of business I suspect.
To say that something is unable to be beaten is intrinsically a claim about the future.