Thanks, But what an stupid business plan, why not sell to every body that you can find and convince
Convincing people is expensive, so its something you only want to do if a large order rests on it. MediaTek's history is in supplying a small number of high volume customers will cellular radio products, so broad marketing didn't make a lot of sense for them. Now they are trying to get into more broadly spread IoT applications, with ULP wifi and embedded cellular modems, they might need to adjust their practices.
Because cellular applications usually require a lot of vendor/customer interaction, and the all the vendors and customers know each other well, very few cellular devices have full documentation downloadable from the silicon vendor's site. Even a company like TI, which provides all information for most of its devices on its web site, required direct interaction with the company for cellular devices when they were the big cellular supplier.