A lot of people here complaining that Soloproneurs only make "useless" "pet rocks".

There is a big bias here, only the pet rock solopreneurs are very public about what they are doing and their success at it, because that is their marketing, YOU (their audience on HN and Twitter) are the pet rocks buyers.

Solopreneurs with stuff other than pet rocks often don't want to share their success and how much they are making especially not to a tech savvy and entrepreneurial audience, as this would just cause more competition.