I have flown first class, not international business. Yes, there is of course a range of first class experiences. Many include expensive additional services. B

I have flown first class, not international business. Yes, there is of course a range of first class experiences. Many include expensive additional services. But a sigificant component of the cost is simply that first class carries fewer people per linear foot than does economy. Allowing the unbundling of services is much more likely to allow the emergence of an "extra leg room only" class, than is a situation where services must be bundled into a standard package. If the prices have to be the same regardless of seat location, and be packaged with an identical bundle of food, blankets, etc, then that's a strong disincentive to attempt to sell a separate class of legroom seats. And it's much more likely that a "standardized seat" will be too short for very tall people than it will be tall enough - and even if it were, that would mean fewer seats on the plane and thus higher prices.