https://www.dailypost.co.uk/news/north-wales-news/extremely-rare-pink-grasshoppers-found-24644249
They're probably less rare than you think - we nearly always see some at Minsmere when we're sat on Digger Alley - Mrs WJ took this pic a few weeks ago for example. Still amazing to see though!
It could easily be the case, they're more common than realised.
With the rapid growth of concrete, tarmac and brick reducing habitats, along with astroturf which seems to be rapidly gaining popularity (three local back gardens here have been astroturfed by the same contractor during July), people are not connecting with nature.
Given the potentially shortened lifespan will reduce the numbers seen over a prolonged period, if that is the right choice of words, along with the general public seeing them, and of course, not forgetting media hype....