I wouldn't say those things are completely ego-less, but I will say that they're not necessarily for personal enjoyment alone.

The function of all that is entertaining guests. Of course theirs must be the biggest and best to win people over. You may then ask why they need to win people over, and you will find it only keeps getting more complicated and torturous to maintain than what any individual's ego could possibly and stubbornly want to do.

I'm not saying the wealthiest are heroes or saints or anything like that. In fact, in some cases all of what I just said is totally wrong and it's just a front for massive money laundering. Having a means for large private gatherings is also ideal for other possibly nefarious activities.

I'm simply trying to explain what humanity and depth exists where you don't think it does. It's not really one single "evil" person, or even a group of "evil" people, but a situation caused by many well-intended constraints. That a system naturally becomes corrupt as a mere side effect of its scale and tiny imperfections adding up rather any intentions is probably the most evil thing imaginable.