Whoa... Like the OP, I'm also a UA Plat / *G (though, definitely far away from a Million Miler still).

In 2017 with the same status, I flew the short-haul in the LH group 35 segments in Y and 6 LH group long-haul segments in Y and did not get so much as a nod from any cabin crew. Maybe because I'm younger than most cabin crew members on my flights -- I have no idea nor do I mind it. My FF program is United, and I have received one-to-one acknowledgement from cabin crew on short hauls on UA [Express] metal occasionally. Of course, when I do fly OS J (both short and long), they've been great to me and sometimes do greet me by name (presumably per their training). And I did get two comp upgrades on LX long-haul (ZRH-NRT outbound and return, for IRROPS and Y oversale, respectively) last year as well. The rare comp cabin upgrade is obviously more valuable than a personal greeting in Y. But, I'm still pleased to read that some LH cabin crew do go out of their way to acknowledge *G pax even if they're not M&M program. Fingers crossed that I get to ride with such a crew this year.