Before the pandemic is over, some people will be proudly saying: "They said X was impossible, but we achieved it".

Others will be proudly saying "X turned out to be a pipe dream, but we unexpectedly achieved Y!"

Therefore I suggest, when you hear "X is impossible" treat it with even more scepticism than usual. Nothing that is allowed by the laws of physics is beyond the scope of human creativity.

*Many* others will be sadly saying "We fell short." Or "We failed." Or "We made terrible mistakes." But they should not be sad. Mistakes and failures are integral to any research effort. Prophecy is impossible.

And don't mock or blame those who fail or make honest mistakes. Just criticise. Bearing in mind that you, too, may be mistaken.