Because that will only work as soon as we reached full saturation of renewable energy production and consumption.
Otherwise it will always be more lucrative to consume the renewable through Bitcoin than using it for everything else.
A EV car fuel consumption would need to cost more than what Bitcoin can make. A very unhealthy relationship Bitcoin has on consuming energy.
The only real possibility is creating a Bitcoin heater system but most of the time I see Bitcoin mines I'm seeing also AC's which increases the energy consumption even further.
And no, the demand for renewable from Bitcoin will not mean we will create and invest more money into renewable energy overall with a net positive it will only add to more Bitcoin mining.