Based on this description, it sounds like someone walking past your unattended desk and bent on disrupting your day but not stealing your data, could enter in a garbage password into the lock screen a few times and lock you out of your own laptop.

I guess the same also works for cloud accounts as well. I remember, back in the mid-2000s, trying to log into my hotmail account (never having failed to log in before) and getting a "locked out due to too many bad passwords". So someone, only knowing my user account name (which was the same as my email address), locked me out of my own account. The problem was, I couldn't remember what my recovery accounts were (I eventually figured it out).

Heck, once I cycled for half an hour with my iPhone in my pocket, and somehow the phone against my leg was in just the right position that it kept interpreting my leg movements as trying to enter a passcode.

Got home, pulled out my phone, and it had a message that it was locked for several hours due to so many failed passcode attempts. Incredibly annoying.

Still, only happened once in well over a decade of owning an iPhone.

I was mostly frustrated that there wasn't some alternate way of regaining access, like via my Mac or iPad logged in with the same Apple ID. Or that the failed passcode attempts didn't start eventually playing a loud alert sound or something on each failure.

The description is misleading. What made the OS create a new keychain was resetting their login password, not the failed password attempts.

(The login keychain is encrypted using the user's password, so it's reasonable to create a new one when the password is changed - otherwise, you end up in a situation where applications constantly pop up prompts for a password the user doesn't know every time they try to access the keychain, e.g. to load saved passwords in Safari. I've seen this happen on older versions of macOS and it's positively infuriating.)

Remember entering password to one service I subscribed to. It was Friday evening. I typed it wrong 5 times and my account was locked out with a message to contact customer service. Customer service was open from Monday to Friday 9am to 5pm. So I was unable to use it for a couple of days. It was painful experience. I found an alternative though and on Monday cancelled it.