> One where the market maker is taking up the cost of providing a market

Does a landlord on a literal physical market take 30% of revenue? I find that unlikely.

How did we arrive here, where supposedly ‘efficient’ digital marketplace is a form of rent higher than actually building physical rent, and expenses on wages and materials for a typical business?

Unfortunately a lot of economic activity in general today is just money-on-money financialism. It is all just gambling and rent seeking and dishonesty. These practices are whitewashed and given various names. The one for rent-seeking is "market making".

Ad platforms too are fundamentally about letting someone perceive ROI lesser than their real ROI, for your own benefit. For me, it falls under the same category as all of the above - zero productivity endeavours.

Maybe we should go back to the previous millenium and make usury illegal. Should fix all of these problems, albeit in a nuclear fashion.