As an example, knowing that a service is offered by a registered company with presence in my area gives me the knowledge "that they know that I know" that if something goes wrong, I can sue them for negligence, possibly up to piercing the corporate veil the company and having the directors serve prison time. From that I can somewhat rationally derive that if the company has been in business offer similar services for years, it is likely that they have processes in place to maintain a level of professionalism that would lower the risk of such lawsuits. And on an organisational level, even if I still have good reason to think that most of the employees are incompetent, the fact that the company is making it work gives me a significantly higher preference in the "result" than I would in any individual "stupid" component.
And for a closer-to-home example, the internet is well known to be a highly reliable system built from unreliable components.
That is literally how civilization works.