Well it's an employee-owned company. Your data is as good as mine. You assert that Wolfram's work is worth less than $1billion. You're quite emphatic about that fact. Let's just do some back-of-the-napkin math to assess if your premise has any validity.
Mathematica has been around for over 40 years. It has 1600+ employees. Tell me, how could a private company make payroll for 1600 top earners without hundreds of millions in revenue? They had no outside funding that we know of.
Obviously this company has made $1 billion dollars in its lifetime. Many times over I'd guess.
Existence doesn't guarantee profitability - they may have investors with a lot of patience and deep pockets. After 40 years, they should indeed turn a nice profit, but I'm not sure if it brings in billions. Many people see their product as educational software.