Baseband chips and sim cards aren't infrastructure, but you still can't compete because getting permission to run one on modern networks is financially well out of reach for most. This is why open source inspectable firmware simply doesn't exist for these things.

All we currently have is leaked 2G and 3G source code for people to build their own off, most notable would be omsocombb

> leaked

"License: Affero GPLv3 for all cellular software, GPLv2+ for some remaining software (libosmocore, OsmoPCU, OsmoSTP, OsmoGGSN)[1]" (https://en.wikipedia.org/wiki/Osmocom)

O.o?

I think that comment may be referring to the leaked Mediatek baseband source. That is capable of 3G/HSPA+ at least, maybe LTE.

Baicells will happily sell you cellular basestation hardware.

Omscocombb isn't leaked code either, just an alternative implementation.