For a lot of B2B SAAS which sells to enterprise, sales people can get decent salaries. An SDR (finds leads and books meetings) could get anywhere from 50-65k Base salary with commissions and Account Executives (AE, they do demos and close) could even get starting salaries of 100K plus. So yes, they get paid through commissions but at SAAS companies, they also get a decent base to start with. Ultimately though, the total comp. adds to the payroll and reduces profit regardless.

at any company the sales person will have a "base", but at none can they take it for very long. even in 100% commission roles if you make no sales you get what's called a draw check because it's illegal to pay less than minimum wage per hour worked