I disagree with this strategy. Alts can bring more profit than BTC in short term. When you get enough profit from alts, then buy BTC and see how it goes. Repeat every once in a while. 
Alt coins do have a huge potential to provide much higher returns that btc because altcoin which trade in cents or few dollars has a huge way to reach till 100$ or more per coins. While btc is already at 7500$ so may not reach 10 times in a year or so . Well if you identify some altcoins which can provide the best return than you can make good money with altcoins too.