that's not the technology

of course it's silly to talk about manufacturing methods and yield and cost efficiency without having an economy to embed all of this into, but ... technology got cheaper means that we have practical knowledge of how to make cheap clocks (given certain supply chains, given certain volume, and so and so)

we can make very cheap very accurate clocks that can be embedded into whatever devices, but it requires the availability of fabs capable of doing MEMS components, supply materials, etc.