"We can observe that many online services close" does not imply "People who make online services have a moral obligation not to close."

It's not a moral obligation. It's that there are structural reasons why most web services have a short lifespan.

That's a problem because it makes it hard to rely on any new service, and that's eroding user trust. At least among people I talk to, there's a lot more skepticism about new stuff than there was a few years ago.