No, it doesn’t prevent a proprietary system from being built, but it does provide the end users/customers a choice to support products that uses an open system.
The first real contender to the ESP8266 is set to release September 1st: the successor to the ESP8266, the ESP32 - now with dual Tensilica cores (and a bunch of other stuff).
I agree. Most mobile games I've downloaded prioritize ads views/in app purchases over making a 'hardcore' game. There are a few exceptions, such as Vainglory, but the vast majority are the equivalent of the super ball vending machine at the grocery store.