My Points:
- BTC is tracable
- BTC is having a huge txn costs
- Time taken to transfer money is more than 10 minutes
- Mining is being done with somewhat centralized servers(pools)
- Several other Alts are now at the market and they performs well in the market
- People use different currencies for different purposes
People are always going to be searching for the "next" bitcoin in the altcoin market. Realistically, it will take alot to oust BTC as the market leader. The great "flippening" has been talked about in the past and ETH has come closest but I don't see BTC leaving it's seat any time soon. IMO, the only way that happens if there becomes greater FIAT entry directly into other coins. Right now the FIAT to altcoin market is limited so the majority of buying and selling funnels through ETH and BTC pairs