No one runs a business with the intention of having sales drop 26% (so far). No one builds a successful brand name only to trash it and be forced to create a whole new one to replace it.
As other posters have pointed out, they're seeing an increase in Stella Artois ads because InBev hopes an increase in Stella sales can offset at least some of the lost sales of Bud Light. The finance folks at InBev had to go out, hire an agency, create ads, and run them, all because InBev marketers damaged their own brand.
This is not a boycott; it's a change in behavior. The comparison is not to other boycotts but to an initially successful product that disappeared due to a change in public perception. A good example is another alcoholic drink; Zima.
https://www.mashed.com/197573/the-untold-truth-of-zima/
Yes, but it is but one brand among hundreds is my point. Does it sting initially, yeah, over the long haul, with the short attention span of the average American consumer, I doubt that it has as much impact as everyone here seems to hope it will.
I'm perfectly happy to be wrong about that, but again, Bud Light is but one among hundreds of arrows in their quiver.