For good (server) search, one needs many layers (Photon, Pelias with OpenAdresses, Overpass, in-house pmtiles, etc.) using many DBs, each needing server ressources or expensive paid APIs.

It's obvioulsy expensive in terms of ops + dev, but also just to host.

It can't scale with only 0,0001 % of users donating to the app.

Fortunately, NLNet's there to fund work, but it's still nonethless only a tenth of what would be needed.

Plus map applications and general search engines don't talk to each other... I don't know why, but it is so. Maybe because all the well-known search engines are closed-source ?