Of course you're all right, but I was seeing this as a more hypothetical "better than nothing" scenario.
Leaving aside the costs for any european band to go to the USA, let's imagine this:
Band: "Damn, we're all locked down and we can't tour at all"
Promoters: "Damn, we're all locked downa nd we can't book any concerts"
(Lockdown ends)
Band: "We'd like to try and play some concerts again damn"
Promoters: "Yeah, so I might have a venue for you, but it's in the open and we have to have seated people and a limited number, so I have 1/3 of the audience and sorry guys, I will pay you 1/3 less"
Would it be extremely naive to assume that under specific circumstances a band would accept this, maybe for a local gig that does not require travelling expenses, just to have some money going which I assume would still be more than what people would pay for shirts online after a "Hey, we can't tour, if you want, we refurbished our stock" message on social media?