Interoperability does not benefit incumbents, but it does benefit entrants.

The cross-protocol clients back in the day used reverse engineering to work. That would not fly today because today's tech culture is less hacker friendly, more litigious. Such a company would not receive venture funding due to its risky nature.

I think there is room for improvement in messaging, but interoperability makes it more difficult. I think it is in everyone's best interest to first ask for better features, let its inventors make a profit, then worry about interoperability once competitors catch up. If the market is competitive, interoperability can be achieved through coalitions. IBM's MCA vs Compaq et al's EISA is an instructive example.