I think it is fair to say that they invested $2B, if it were a dead end there was a chance that the machines would not be that useful, or at least they would in

I think it is fair to say that they invested $2B, if it were a dead end there was a chance that the machines would not be that useful, or at least they would incur a large loss on paying a premium for them at the time. Conversely it shouldn't be frowned upon that they invested and believed in BioNTech's methods that made it trivial to almost immediately produce a vaccine candidate on an unproven platform. Moderna likewise had their vaccine candidate within days of having the sequence, vaccines are mostly pretty easy when your first try works!