Sure, if some engineers told you "we are putting this person on Mars with a 99.9 probability", and the rocket in fact reaches Venus, the engineers are incompetent.
Also, polling in most European countries doesn't go this far wrong, on almost all polls. So it's not like "accurate polling is impossible", it's just the polls in the US that seem to have some problem (though there have been some spectacular failures in other countries as well, which itself may lead to some thoughts on the value of polls in general).