Well, bitcoin is used much more than other coins and that is the reason that its transaction fee is high and speed is a little less than others. But as soon as others coin will be used to an extent at which Bitcoin is being used, their fee will increase too. Ethereum is the best example of this.
Well, That's right. Bitcoin is now very demand in the internet. It is now legal in many countries like Philippines, Japan, China etc. This is the reason why fees are now getting higher. But, if the demand of it will try to decrease, i believe that it will also decrease. But, it is impossible to happen because as long as innovation exists, Bitcoin is getting famous in the market.