Once Silicon Valley’s highest-flying darlings, companies from WeWork to Uber Technologies Inc. have collectively lost about $100 billion in value this year, prompting some startup executives to talk up profitability over growth as venture-capital investors grow more cautious about spending.

In recent weeks, car-subscription company Fair and software company UiPath have downsized. Scooter-renting company Lime has rejiggered its operations to prove to investors it can turn a profit.

“We’ve...