> The companies were always trying to get coworkers together and have events (on company time) that got teams mixing and socializing across departments.

Really depends. These are people in the same social class. But I have never seen a cleaning lady that works as a contractor being invited to a corporate party event.

Is that the standard for ‘employee camaraderie’ that you were ever used to during your career? I have only been working in the “white collar” world for about 20 years but in any company big enough that they contract out cleaning, the cleaners are not attending the company parties. And put yourself in their shoes, do you actually want to come to some tech company party after work? I would have as much interest in attending a party full of say, rich Hollywood producers, which is to say zero. (The only reasons to want to attend a party of a higher social class in my opinion is networking or celebrity-spotting and neither seems relevant in the context we’re discussing).

> But I have never seen a cleaning lady that works as a contractor being invited to a corporate party event

Why would they? The corporation is not their employer. Those people are not their coworkers.