How long could Humanity last on nuclear fission power alone?

If humanity were to take every gram of usable radioactive fuels, from uranium and plutonium, to potential fuels such as thorium from everywhere on Earth and extract every last kilowatt-hour possible, how long would that last?

If breeder reactor can provide almost limitless source of energy, why the need for fusion energy? Just use breeder reactor will do.

So my point is Breeder reactor from fission itself can already last for at least hundered of thousands of years and we already have the means to produce such breeder reactors with our current tech. Meanwhile fusion reactors are still experimental. So im asking why not just focus all resources on building breeder reactor since its already proven to work and forgo fusion?

Better than renewable really. Clean up weapons waste and SFRs. Waste to Energy!