I think this underlines the core problem. It's really hard to make a fully informed choice of provider based on costs, and they deliberately make multi-cloud expensive.

Egress costs are fairly clearly a vendor lock in strategy. If I want to transfer 1TB to run on cheaper compute at another provider, that costs me $90 (edit) on AWS as opposed to $0.24 at wholesale prices. It's unlikely to be cost effective so I choose AWS compute.

EDIT: thanks to someonebaggy for pointing out my decimal point error.

Ninety dollars to transfer a terabyte is clearly ridiculous.