Personal opinion, I don't think this strategy must be followed. There are coins which is good in many aspect if compared to Bitcoin. And if we see this for long run, those and many altcoins have greater chance to flourish. I don't want to enter the speculation about surpassing Bitcoin, nobody can guarantee that, but I believe these coins will give a good return, and if you compare the percentage of return with Bitcoin, you will see a good difference.
Yeah true enough. It's hard to speculate on these things, but I wouldn't be putting all of my bets on the Bitcoin and ignoring the rest. There are lots of other good things on the go out there too. Altcoins are hard to sift through because there are so many, but if you take care and look through them enough, there are bound to be many worth investing in. Especially ones that are linked to real world purposes or causes.
No investment strategy should follow an "all-in-one" approach. That's just dangerous.