Earnings fuel bull markets. Amazon is case and point. There is a reason this stock has nearly doubled the past 2 years.
The bull market is long in tooth. Everyone points this out. But so what? There are no rules that state it can not go on for a lot longer. Earnings continue to beat expectations. Top down analysis and bottom up analysis all show the same thing. We are in a bull market. Until these conditions change buy the dips.
This is not to say the rubber band is not stretching. Companies like SNAP have a 15 billion dollar market cap and are expected to never produce a profit. When the next down turn in the economy comes, funding for the silicon valley mania is going to evaporate. Until than enjoy the ride.