The mainstream strategy is to invest in highly diversified ETFs. Investing in just 4 companies would be considered exceptionally risky and contrarian by most people (I would personally also advocate going up to 20).

Also, not to nitpick, but Jobs and Gates are no longer running their companies, and Zuck is down to part-time. I don't consider either of those companies at the same level of growth potential as Apple back when Steve was running it.