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).