Just to spell this out more clearly for the back row.of the classroom:

The price is what the customer will pay, regardless of your costs.

Economics teaches us that a big difference between cost and price attracts competition which should make the price trend towards the cost.

Practice taught me that that "should" is doing a lot of heavy lifting here and it's often not the case, even across long time periods (years) that should allow competitors to emerge.

For example I calculated the cost of a solar install to be approximately: Material + Labour + Generous overhead + Very tidy profit = 10,000€

In practice I keep getting offers for ~14,000€, which will be reduced to 10,000€ with a government subsidy and my request for an itemized invoice is always met with radio silence.

A big difference between cost and price is often won at the expense of many years of concerted R&D, though

Only if the barrier of entry is low.

Which it won't be, if at every turn you choose the hyperscaler.

Economics has a lot of other lessons teaching us why prices of major clouds have remained somewhat expensive relative to cost

If this is the case, cheap bandwidth for AWS, when?

Exactly.