I think this is an interesting/valid observation. When I first bought my TJ three years ago, knowing nothing about any of this stuff, I took it straight to the top 4x4 shop in town. Their proposal included the Teraflex 3" TJ lift for $2,473, plus all the other usual stuff - Yukon regear, Detroit TT, TF Shorty SYE, Tom Woods DC, etc., to run 33s. Total ticket $7,664. Still have the proposal and refer to it from time to time. Haven't pulled the trigger on any of it three years later, except that I threw in some 2" pucks and new shocks. Still deciding on a lift . . . Lol.
But to your point, I think TF may be the shops' go-to suggestion for newbies. If there's good margin and they know they're dealing with the uneducated, it just keeps it simple for them. Especially in the big-budget bought-not-built JK/JL arena. Seems us TJ owners spend a little more time investing our own blood, sweat and tears into our rigs and end up here on this forum debating the merits of our preferred brand manufacturers, mods and build plans.