There is alot out there still. I feel like it does make some sense as long as you go in as a hobby and not hoping to earn anything. Keep it fun and creative. Make yourself unique.. And have fun!
Yes, but only if you have a lot of money to invest in advertisements, server hosting, plugin development, graphics, etc.
If you aren't able to do the above, then your answer's probably gonna be a no.
It's really hard to start a successful minecraft server without having a lot of money to back it unfortunately. But if it's just for you and a few friends, then by all means, go for it .
I think you can make a successful server only if you make a new game mode and advertise it. Something really fun and enjoyable. Also if you live in a country other than usa and uk you can advertise your server as being from the country you are fromand probably attract many players' attention. After getting some players to play you can then advetise the server even more as a global. You can make it possible if you have some money to spare or else its pretty much game over. But if you want a sever just to play with your friends it totally fine and you should go for it.