If ever there was an antitrust situation it is Google and Chromium.
(a) Widespread use of the engine which means its behaviour is what is largely defining the rules of the web today.
(b) It is driven by the financial interests of Google, specifically their Ads division. For example: Google recklessly adds every API under the sun even though they know they are being abused for fingerprinting. And they have long lived first party cookies which are used for re-targeting, attribution and conversion tracking. Both of which have major impacts to ad revenue.
To be clear, it's actually everyone else that benefits from this sort of API. Regulators (eg CMA) are the ones stopping Google from removing third party cookie support from Chrome without a suitable replacement. The world is more complex than what you can see at a glance.
(a) Widespread use of the engine which means its behaviour is what is largely defining the rules of the web today.
(b) It is driven by the financial interests of Google, specifically their Ads division. For example: Google recklessly adds every API under the sun even though they know they are being abused for fingerprinting. And they have long lived first party cookies which are used for re-targeting, attribution and conversion tracking. Both of which have major impacts to ad revenue.