No one buys CDs but Taylor Swift still makes a lot of money from her music. Doesn't negate that making music is economically worse than ever.
Most people book flights online, travel agents still make a lot of money. Doesn't negate that travel agency as a business is economically worse than ever.
Most people have cameras in their pockets that can take good photos, photographers still make a lot of money. Doesn't negate that being a photographer is economically worse than ever.
Hopefully, you see the pattern. You don't remember that companies that are no longer around.
Many of those companies like duolingo have already collapsed in stock price with YoY growth dropping off a cliff. It is happening, it just isn't instant.
And yet those companies aren't collapsing because it became easier to rewrite their software, but because llms themselves have replaced a core part of their business (such as translation or simple art).
Seems like so far the market is not convinced at all that SaaS companies as a whole are any more disruptable than before.
That and talking to a lot of users, Duolingo reduced the quality of their service moving to LLM generated content -- a lot of people moved to other apps.
If its so good why aren't you rich?