NBA and NHL Playoffs: Why Are They Spaced Out?

I know that playoffs can be one game in each round (NFL, CFL, NCAA Tournament Basketball) or seven games (MLB, NHL, NBA). I also know that playoffs can take ten days (NCAA Tournament Basketball), four weekends (NFL, CFL), a month (MLB) or up to three months (NBA, NHL).

In this opinion, I am going to talk about the NBA and NHL. Each league has their playoffs with the teams taking breaks between each game. I don't understand why it can not be like baseball.

Why can't they play two days in a row?

Why do they need a rest between games in one city?

Why does it take three days to play in two games at one city?

I understand that games three, five, six, and seven are two days apart from games two, four, five, and six because of travel.

You know, I think both the NBA and NHL should follow the MLB playoffs structure and play games 1-2 & 6-7 at the higher seed and games 3-5 at the lower seed. Also, the leagues should play to the following playoff structure: Game One, Game Two, off, Game Three, Game Four, Game Five, off, Game Six, Game Seven (I don't understand why there is a day off in between games 4 & 5 in the league championship series or World Series).

That way, there would be less travel time and more sooner games would end and championships can be crowned.