The simple goal of bitcoin can be achieved as one of the forms of economic investment beyond the monetary value or value of the asset from the material point of view

The competition of bitcoin is itself

I am sure btc someday will be a good fortune

ETH is currently doing good so there's a chance that it might be a good competition for bitcoin.

I don't think it will happen within near future, but it is possible

 Bitcoin is more popular and familiar to common people because it is the first of its kind and  people started to buy bitcoins. Because of that it price increases day by day and it always appears in the headlines of all news portal. All other coins are not so popular. Thats why people prefer bitcoin than other altcoins

I think btc has no reason to fail them as currency.

The bitcoin value will definitely decrease until it is zero

In fact, it is difficult to conclude that Bitcoin will decline due to accessibility constraints

Because it maintains the stability of state finances, and prevents cybercrime

you also have to use your mind and your instinct to win it.

I think because  the value of Bitcoin is the trust and it's not own currency any countries you can use for transaction to any countries in the world.