Could the answer to the Fermi paradox just be that aliens don't have the uranium required for nuclear propulsion in their home star systems?

So far nuclear propulsion is the only method we know of that can get a ship to other star systems that doesn't take a ridiculously long time, and should we not discover spoopy warp technology I assume it would be our only method barring out megastructures like stellasers.

Our system only has uranium, thorium, and other shit because two neutron stars merged near us and made a kilonova that delivered about a moon's worth of material to our system a long time ago.

I don't think it's too big of a stretch of the imagination to think that alien systems might not have had kilonova explosions near them to deliver uranium.