Because it pioneers the digital currencies and being the first one. I think it is just a disrespect if some coin would exceeds its price. Also bitcoin had proven anything what skeptics says and being a top currency it would still be develop to be the one used for the cashless society era.
The development will continue, and that is good because it will result to an increase of adoption.
Even how many good coins will exist in the market, and even better than bitcoin is actual used case, but you cannot change the reality that people are supporting bitcoin more compared to altcoins, with bitcoin being in the top, the market is performing well in overall, so it's better not to change anything.