I believe that they're popular mainly because well it was the first of all cryptocurrencies to be made. Honestly most of the other coins are scams and greedy ways that the developers make money. The only other coin I can think of that isn't a scam are dogecoins! What do you think?
Every other which does not have any financial utility will lose . Even if it is Bitcoin, I dont know much about dogecoin , Most of the coins are nothing but just copy paste of Bitcoin with adjustment in POW and coin supply.
1. Yes it is true developers are making a money, and I think its quite ok because world is now more programmable as compared to putting trust in the hand of Centralised institutes.
2. What do you mean by Scam ? The place I come from people call Bitcoin scam. India.
3. Cryptocurrency came into mainstream now, it is like any other tech like AI which will be a hit in next 10 years same thing will follow with that.
4. Money talks.