While lock-in might be a motivating factor and benefit, it's also just that it's really hard to make something that works with a competitor's something-else wit

While lock-in might be a motivating factor and benefit, it's also just that it's really hard to make something that works with a competitor's something-else without your competitor sharing all their details. It's much easier for a company to guarantee the experience of the end-user when they only have to worry about things they have control over. You can't just make that kind of simplification as if it's proven fact.