Can't secure supply of 32mhz Automotive grade oscillator - why is this?
Isn't a high temp 32Mhz oscillator a common thing in automotive just
like a 32Mhz oscillator is in a consumer product?

In general there are many more parts meeting commercial specs than there are with an automotive qualification.  This is not unique to oscillators specifically.
When selecting a part you should check where the product is in its life cycle.  You use tools like &quot;part intelligence&quot; to find out this information.  This will allow you to make an estimate of how long the part will be available.