The way you ultimately solve this is by aligning incentives, eg "platform engineers get fat bonuses/promotions when the products built on top of their platform kick ass."
The extra bit of empathy makes all the difference, because without fantastic personal communication, 'platform' could be a waste of time for everyone involved.
And honestly other eng teams kind of are your customers. They may not pay you directly, but they also help to build your product and the company that cuts your (and everyone's) paycheck.
If my coworkers need my services, then that's because they are developing something that a customer needs. I think of it like a dependency-tree. As long as you trust your company to not have multiple teams develop something that will never see the light of day, or something the user doesn't want or need, then this mindset is absolutely a good one (Sadly been there, done that too).
Btw this can be true of other departments as well – for example, SaaS product marketing is often an entity that exists to serve internal "customers." Product management can be envisioned this way as well.
>And being able to effectively and quickly incorporate feedback from consuming teams into the product.
Without that, you can have a quality platform team pushing out good products, but if it doesn't align with what other teams need or you don't expose good override hooks, then the end effect is the teams will fragment into doing what works best for them.
The things I've seen built with Excel and Access.