It's actually 12.5 BTC since the halving block reward happened last july and each 4 years It should continue to get halved. miners will get the fees instead of block rewards and that should make our bitcoins cost more since no more are being mined logically. If bitcoin doesn't get developed over the years then definitely a new altcoin could take its place. All bitcoins should be mined by 2140 and we would be all dead so you shouldn't care much anyway.