It parts from a Google Trends observation as an indicator for "retail interest", which is highly speculative. First, Google searches for Bitcoin are often related to speculation by Average Joes, not to cryptocurrency usage in the retail sector. They may however use the word "retail" in the sense of "small investors".
that's what they're talking about---retail vs institutional investors.
none of this is surprising. it's institutional buyers (not small fish) who usually load up during the bearish/boring stages of the market cycle. retail comes later. retail interest usually spikes in the later stages of a bull market when hype is strongest.
right now the altcoin market is dead, google trends is dead, the forum and crypto twitter is dead. these are still the early stages of the bull market. we're still a ways off (several months at least) from the sort of retail hype we saw during 2017.