I understand why someone would think that, but in my experience the economics for product owners aren't significantly different between scrappy underdogs and massive firms.
First, most new products start as a web app. If the product is profitable (or convinces someone with money that it will be profitable) the product owner is granted additional headcount to allocate.
In my experience, adding more user-requested functionality almost always has a higher expected return on investment than making fully native versions of the product for iOS, Android, or Windows. (I have no experience making software for Mac.) As much as I like using native apps myself, there are plenty of cases where I couldn't make a case that creating native versions would have a positive return on investment at all.
In summary, the number of products that are profitable enough to afford native development teams is small, and the number of those products where the native development team would pay for itself in increased profits is smaller still.
There are plenty of exceptions like games, legacy software, realtime systems, libre software, low-level utilities, Mac-only dev shops etc. But otherwise the economics don't seem to work out.