A big reason software is free is users pay to display. We may write the code, and we may rent computers to serve the code, but the rendering, interaction, and magic happen on devices and infrastructure the user himself pays to run.
End users pay for compute, pay for internet, pay for running costs (electricity), refresh their hardware, and manage versions.
You can't buy access to only Uber, because you must first buy a smartphone; then access to Uber is free. In practice in the developing world, this works, because people have smartphones and are willing to pay $1000 every two years (plus another ~$1000 in data) to refresh their hardware and software.
The more competitive the world of software gets, and the more open platforms become, the more attractive a new monetization scheme gets.
Imagine a world where Uber subsidizes your phone and data plan in return for being your default "transportation provider"--or just being preinstalled on your phone.
Or, instead of Google paying Apple $15 billion a year to be the default search provider on iOS, what if Google paid each of Apple's 1 billion iPhone users $15? (That's not realistically feasible with fiat systems, but is extremely feasible with crypto.)
For a historical example, Facebook's expansion in Africa was supposedly heavily attributable to Facebook Zero, which waived data usage charges when using and accessing Facebook. Wired Magazine thought about Facebook subsidizing your phone. Amazon already has ad-supported Kindles (ref link, non ref Amazon Smile link).
What is the next step of this? Instead of companies subsidizing your hardware, protocols will. As long as all purchases you make on your phone go through Solana, or Avalanche, or ZCash, the protocol or DAO will subsidize your phone. There are probably zero-knowledge proofs that can be run on-device to attest that spends did actually happen without revealing the sender or recipient of a spend.
When all is said and done, the largest company with the lowest CAC/LTV ratio will have their logo on the back of the phone.