[avianlyric]

Cost and power efficiency. If you want cheap portable electronics that have batteries that last forever, then you need to build SoCs that have exact features needed for a specific application and no more.

Maintaining software compatibility would mean sacrificing either price or power consumption. So a manufacturer can choose between spending money rewriting the software, or having to pay anywhere between 15¢ to $100 more per unit. If you’re making millions of units, then savings from using more limited SoCs will quickly pay for an army of software engineers.