That was a different world. France and Britain today have nowhere the kind of force projection the USA does, via its military bases and aircraft carriers.
The US probably wasn't in preventing an invasion of Egypt, but if not restrained I'm sure that Britain and France could have realised their objectives, and if they had had a continuous need to realise different changing objectives they would have retained more capability.
France and Britain used to be two of the world's largest imperial powers, and at any time you could plausibly claim France and Britain alone could defend global trade routes, Britain, at least, still was.
You really aren't making a case for it being an easy, cheap job.
I think these trade routes etc. will stop mattering rather soon. Batteries are coming and once that's here the oil trade's gone, and then you have no need to export things to get something to trade for it, so in a decade or so none of this will matter.
International trade will go from being mandatory to optional, and thus become much less important.
France and Britain alone used to be able to defend trade routes. I don't think it's a huge expense. It really is good for essentially everyone aside from the US itself, once the disruption is over. Obviously we'll have some kind of crash though, but I think that was inevitable with or without this.