I don't think anyone's saying that capitalism is directly at fault. Theoretically, a fully free market (assuming that companies always have consumer
and shareholder interests at heart) should be optimal, encouraging healthy competition, choice for the consumer, and the economic freedom to found your own startup. Unfortunately, the realities of the free market encourage economic foundationalism and excessive bureaucracy. Despite the free market's relative strengths when looked at from purely a business and consumer perspective, the fastest way to earn revenue and (eventually) break even is to have a company playbook which encourages business decisions that are completely antithetical to what you'd expect from a free market company. After the inevitable IPO, they slowly tend towards maximizing shareholder profit in place of ensuring consumer satisfaction (there are exceptions to this rule-- Apple and Tesla are good examples), and the results are more acquisitions, more profiteering, more tax avoidance, and more focus on the bottom line than putting out a good product. Particularly harmful is how an unregulated free market encourages trusts and oligarchies -- the latter of which we still can't solve today with legislation alone.
For every airbnb or Facebook there are a thousand of acquired startups who kept thinking short-term and forgot entirely about long-term. Which is a shame, because I've no doubt that many put out a quality product -- and I've also no doubt that the company which acquired them may very well have killed said company's specific product two seconds after filling out all of the paperwork. See Google's numerous acquisitions for proof of this.