Let's just put aside intentionally not understanding my point for a sec, OK? I hope we do agree that the wider the lens, the less important IS is, right?!
As for me I really don't care for IS at 50mm, especially hiking where weight is #1 concern.
I can hand-hold 1/8-1/15 at 50mm which should be enough. If I need longer exposure, I but the body on the backpack, hold it to a rock or tree, whatever. IS should not be the solution for taking a decent image at 50mm. At 200-300 it is. IS at 50mm is more marketing than necessity.
Less important doesn't = not important, or as you said, "Marketing $ hit." But you are right. The IS module is prohibitively heavy.
IS is not
the solution for taking a decent image, but it is a tool and good to have. There isn't always a rock or tree available.
Besides, in low light it can help a great deal. Not for you? No problem. Calling it what you did is your personal crap, not reality. I'd have happily paid for IS on my 35, 24-70, and 135 had it been available at the time from Canon. It absolutely helped in low light when I had my Tamron 15-30. Especially for indoor shooting where flash is not an option. Not everyone is out hugging trees, rocks, or backpacks.
Saying you don't want or need it doesn't mean a bunch don't. Especially shaky old men like me. Marketing's job is to make a product appealing to the market. You ain't the market for IS on short focal lengths. That doesn't make IS on short focal lengths $ hit for the rest of us. Why would I want to shoot a person indoors at 1/8 sec without IS when having IS would make that shot easier or even more likely to be on focus? Mountains and rocks don't tend to move. People do... so a faster shutter speed helps. Yes, ISO can be turned up, but there comes a point where that isn't desired.