When I bought my 610 the Intel was optional for about $20 extra and the standard one was a Dell branded Broadcom chipset. Like me you probably selected the Intel chipset because of Linux. AFAIK the Intel's were always available as an optional "upgrade" (probably because Intel required it by contract).
When I bought the 610 and for several years later the default Wifi on all the Dell Laptops (that I I looked at) were Dell branded Broadcom chipsets. The typical upgrade cost as I mentioned was anywhere from $20 to $50 dollars. That's a hell of a premium on Laptop even when they still cost upwards of $1500 and it's astronomical with prices half that.
But as I said when I checked the other day (on the models I looked at) the Dell branded option isn't even there anymore (and that's astounding in itself given Dell's desire to Brand everything possible). I couldn't even find laptops with Broadcom Wifi chipsets (I didn't look that far, just at a few major models and Brands). That's a hell of a change from default on every laptop at Dell. This is anecdotal evidence at best but for me it's pretty conclusive when taken into account against Broadcom's earlier statements that they would release FOSS drivers when Hell froze over (I believe the actual wording was Never because it would reveal competitive information). I can't see any other reason they would release FOSS drivers other than as mentioned in the thread that they got tired of updating their drivers and want to pass the burden to the Kernel team.