Bitcoin is a PROTOTYPE. All it has is a three year head start which has given it a massive network effect. It has a reclusive, anonymous creator who holds 5% of all bitcoins that will ever be mined. If just one of Satoshi's coins started moving the entire bitcoin community would collectively shit their pants.
I have always said that if Bitcoin was created tomorrow it would be derided as a heavily premined, incredibly slow shitcoin. But it is bitcoin.
I think the mistake you're making is that you're looking at it from a technological point of view. ok - from that perspective, Bitcoin will be (and has already been) superseded. Over the last year every type of improvement has been made over bitcoin's technical properties - new algos, confirmation speed, anonymity, contracts, you name it.
However from a MONETARY point of view, Bitcoin's technical obsolescence hasn't meant jack. None of these new coins have even made a dent in its marketcap. In fact, the reverse has happened - Bitcoin's status as a cryptocurrency reserve has consolidated, not waned. Every new exchange that appears prices everything in Bitcoin first and dollars second. 2 years ago, some exchanges supported markets in LTC and XPM for example but that's very rare nowadays. It's BTC all the way which means that comparisons with social network brands such as myspace vs facebook are erroneous.
Sure, technology will advance, new coins will emerge which "fix" bitcoin's flaws and they'll get used on a day to day basis possibly, but it doesn't look like any of them will ever supersede bitcoin as a monetary reserve. Bitcoin's marketcap will continue to increase even if it isn't adopted for commercial transactions IMO.