As for "all things can be accelerated", the question here is more "how unique is the thing being accelerated?" (and so I would agree the wording in my comment was slightly off), as this argument about the grim trigger holds up if and only if the specialized hardware being used is not valuable for other uses (including other coins).
As an example of what you can conclude with this thought process: if you are a small "startup coin" you should seriously considering a proof-of-work scheme that is weirdly unique in that it forces people to not be able to reuse hardware they have from another (particularly if more valuable) coin.