Absolutely! My experience is that I have NEVER been acknowledged in Biz or First class, but almost always in Economy. Am sitting in the back of a flight right now, my partner & I both got a welcome from the cabin senior, first service on meals & champagne + real wine on request.
This is the first flight in 8 flights in Economy though - on none of the Biz flights did I get an acknowledgement.
It is quite unfortunate - plus I hear rumours from the lounge staff that Gold Elite may not be invited back into the First Class lounge when it reopens in the summer. This would really devalue GE and relegate it to nothing more than a slightly glorified Gold.