Why can't we drill to the mantle?

I'm puzzled, why are we unable to drill down to the mantle of the Earth? We've advanced so much in technology, shouldn't it be feasible by now? After all, understanding the mantle would greatly enhance our knowledge of geology and the inner workings of our planet. Is it due to the extreme heat and pressure that would destroy any drilling equipment? Or is there something else we haven't quite figured out yet? I'm genuinely interested in knowing the reasons behind this apparent limitation. Could you please elaborate on the challenges we face in attempting to drill to the mantle?