Investors clearly want them to be profitable; maybe not now but eventually.
They have a $450m valuation and $150m in sales, for which they get 5% ($7.5m) [1]. According to Crunchbase, they have 50-100 employees. Assuming only 50 employees, they are spending at least $15m in wages (plus health insurance, etc.), plus fixed expenses (SF building, AWS, etc.) and advertisement.
So there is no way they would be making ends meet with their 5%. Even assuming they become 5x bigger while keeping the same expenses, they might still be losing money. The only way for them is to raise fees.
Sure, another option is to keep costs down, everything streamlined, don't spend on advertisement, etc. but as others pointed, you can't pick that route if you have investors.