People from outside Bitcoin, looking in from the stock market and trading world brought their language with them, and that language was totally inappropriate. No one would claim you should "diversify" your saved photos in several different file formats. This is exactly the same.
Bitcoin is not a stock, despite stock like charts being used to display its price. Bitcoin is a protocol, it is like a file format for storing money. You don't invest in ZIP or RAR, you invest in companies that use those file formats to do work. "Computer illiteracy fallout".
The price of Bitcoin doesn't matter. Business models and software matter. Adobe doesn't make money out of the TIFF and PDF file formats; they make money out of selling boxed software and online subscriptions. Bitcoin is like a PDF to store money. This is hard for many to accept.
No one today remembers the Replica file format. It was introduced around the time PDFs started to be used. Replica failed because they couldn't get people to use it. Adobe won by giving away Acrobat Reader and flooding the market with PDFs. Then they sold Reader Pro...for $500.
A quick diversion; pirated copies of Adobe Acrobat Pro increased the penetration of PDFs online, and increased the demand for the paid version of the reader software. Piracy is frictionless software distribution. In Bitcoin on ramps _must_ be similarly frictionless.