I think Dorian is referring to the 'R games' while the OP is actually saying the flights are either sold out in J or SEs are getting the seats up front. Business travel has been picking up since last year so this is likely a reflection of that.

AC is not doing a summer promo this year (for reduced e-credits), likely because they feel they can keep their front cabins filled with more revenue seats.

It really depends on what routes you're flying and what days. A peak business route on a Monday morning or Thursday evening can be tough even for an SE to upgrade.