This is - partly - true. However, Bitcoin also shares characteristics with stocks: A Bitcoin is like a share of the Bitcoin ecosystem.

The Bitcoin ecosystem can be loosely compared with an organization or even a business, but it has a much less centralized structure. But it has the character of a group, because there are people "inside" and "outside" the ecosystem - as long as not everybody in the world is a Bitcoin user.

Another common point with businesses is that Bitcoin competes with similar projects, and although no one of them has surpassed it so far, it's not impossible (Ethereum did come somewhat close).

That means that the financial return of the "Bitcoin revolution" can be shared with other coins. From this point of view, it's like a company that did a significant innovation - it has a competitive advantage over others, but can be surpassed by them (e.g. Nokia inventing the smartphone in the 1990s, being completely marginalized in the 2010s because Apple improved the concept significantly).