There's at least one company that does tweak (iirc used) airliner turbofans by taking the fan part off so they just have the turbojet (which is already tuned to mostly generate rotational energy to drive the fan turbine rather than produce thrust itself) and use that to spin a generator. Obviously, it's a bit more complicated than that in reality, but there are quite a lot of old engines no longer certified for flight out of an abundance of caution but that still work fine, and a market for high-power generators that don't need to be the pinnacle of efficiency (originally as backups just for occasional use, and now because of AI companies caring only about speed and not about cost).