Why would individuals buy relatively expensive equipment, set it up and manage it, without the potential for return on their investments?

The only reason Helium's LoRaWAN coverage is expanding rapidly is due to the crypto aspects of it.

Nobody wants a corporatecurrency

And there is no human coordination mechanism without the freely convertible currency

Blockchains provide the open source rails of all the account management and distribution, easing development costs. The infrastructure is already built compared to alternate ways of attempting to do this

have fun doing that without a blockchain

Sort of, Helium no longer sells hardware and the community votes on third party manufacturers to be approved for authorization on the Helium network. This has helped distributed hardware delivery more than any single organization was prepared to do, with the semiconductor and supply chain issues.

There is definitely an opportunity to sell overpriced hardware into the community then.

There are some other antenna-blockchain systems out there that look more like "schemes to sell hardware", such as Match X. There is a big and burgeoning market for these "passive income" things, people install hardware to earn a cryptocurrency.

It is definitely worthwhile to sell the hardware if you can.