Hmmm people dont go to the stores just to play "exclusive encounters". They go to stores because they havent got a home game, or they want to meet new players. The exclusive content has nothing to do with it. Or that's my guess. If that is wotc's reason, it's a terrible one.
Of the 7 people who frequent my table on a weekly basis...
At least 5 have a home game they play in. (One's my kid.) EO &G? play in G?'s game, ZZ & GR play in SJ's game, EH plays in my home game. I'm not certain if CB & W play in a home game or not, but they arrive together.
And I run a home game, duh... so, of the 8 at my table, I am aware of 6 who have non-AL play happening.
And then Matt's table. Everyone of Matt's usual 6 has a non-AL game they are involved in. (They mostly were my crew from sept 2014 to feb 2015.
Same for Shannon's usual 5. 3 of whom play with one of Matt's, run by one of Shannon's players.
I don't know about the other two GM's... but their players also don't show up early to ensure seats at their particular table...
We have one kid who shows up once every month... His mom drives him about 120 miles. Not so much for him getting to play, but for him to experience multiple different GM's, so that his own GMing gets better. (And he picks a different table each time. Great player... for his age...) Actually, they arrange to make the monthly shopping run on game night so he can play - so it's not JUST to play, but it adds a 4 hour block to the 2.5 hour each way drive.
And every group
So, at least in Anchorage... we have about 1 person per 10,000 people in the city showing up for AL play. And most of those are coming for something other than just the opportunity to play at all.