Are there any companies that work for days without human intervention?

Online digital content, like paid courses or an author selling their own books, may come close once a sufficient amount of marketing material is out there. Email funnels can be automated, blog posts can be scheduled (and recycled), payment gateways and whatnot can handle the actual transactions.

Simple apps and games don't necessarily need to keep getting better all the time; a successful one could likely coast for some time without needing much intervention.

google search, netflix, facebook, gmail, roomba, apple, microsoft, slack, youtube, AWS, wordpress, github, jira, the list goes on

I'm not convinced any of those would last even hours without an army of SRE's holding them together.

They all have support. True. However at my gig at my previous Job I have gone many opslead shifts without incidents. In fact most incidents were because someone added something new. During code freeze, we coasted multiple weeks without incidents.

SREs job is exactly this. Prevent future incidents. Prevention is much cheaper than cures (mostly)

Blogs for sure

So I guess SpaceX, Tesla, Intel, Apple aren't tech companies.

Agree with this rhetorical question. What mlboss said should just be "automated company" not necessary a tech company.

With that definition, it's also unreasonable to me that 100 years ago, there wasn't any tech company