For a minor explanation, support is just prohibitively expensive no matter what you do, and quite frankly the only people actually capable of support is going to be the devs who made the product for various bugs/issues, and that is just a handful of people, some of whom have left the company even.

Finding good support is also hard. I worked in product areas with dedicated support for paying customers, and the number of support staff that I would consider actually helpful is precisely 3 people, out of a few hundred. Those 3 people are paid a ton to keep them around, and while I don't know exactly what they're paid they usually get moved up and into a role that at minimum exceeds typical senior eng pay, the rest just bounce tickets back and forth collecting traces with at best a poor understanding of the product. On average no understanding.

Another problem is that a good support staff would probably do better to be a dev anyway, the knowledge required is pretty much the same, just missing development experience.