You’re quoting capitalism’s sales pitch of capitalism.
Go to your local tent city in every city if you want to see what “voluntary” looks like, dying of exposure and police capital defense force harassment while serving as capitalism scarecrows to keep the working poor scared shitless into “voluntarily” showing up to be exploited for already wealthy people’s further profit for their unquenchable greed.
Capitalists aren’t even willing to admit being greedy, only acting on “rational self-interest.” If you want to believe what capitalism claims to be, you do you. If you want to see what capitalism is, use your senses and your critical thinking skills.