These are two "almost pure" approaches to business – Buffett represents the old-fashioned reliance on reliable businesses and their traits that have passed the test of time; Musk represents the promises of disruption, potential for very fast expansion in coming years, and indeed, bubbles and manias where this obsession often leads because it's much easier to pronounce big words and get enthusiastic than to provably produce billions by hard work.

Both approaches have been important. If the Buffett approach were a little bit more extreme and dominating, there would have been no progress. If the Musk approach were a little bit more extreme and omnipresent, everything would have been just bubbles and P.R.

Different industries have different typical time scales of innovation – the timescale τ after which the performance or profits increase by the factor of e or the expenses drop by a factor of e or something of the sort. For some kind of products, like candies, you don't have to watch the innovation every day. In some other fields, like the hi-tech stuff, you do have to follow what's going on every week.