Is there a website where I can view the wealth distribution of BTC and different altcoins?
I know such data are only estimates (address != holder, exchange wallets, etc.), but would still like to get a feeling of how different coins are distributed among its holders.
You can only see this in your bank accounts! As for blockchain technology, they do not provide this service. That is also one of the reasons for the high value coins. Those who have lots of money often sell it to buy coins to launder money. That's why identities are never revealed.