In my limited experience it seems a lot of people are just weirdly but absolutely terrified of being wrong (I used to be one of them once upon a time) so they will either not say anything either way or they will double down to the point of idiocy (I have done both).
That is a lot of coffee O_O I remember when J used to drink that much during uni days. When assessment period ended (can't remember if it was when he was graduating or earlier) he decided he would stop as he didn't need to stay awake anymore and the withdrawal symptoms were pretty ordinary XD
Yep, that's how it often goes but you said, "used to be," so it seems you've wised up and I reckon you are probably better for it.
I had a thing happening and that meant long hours and that's where coffee comes in. I don't necessarily need it to keep me awake, it's just something that seems to go with long hours I guess.