so when the New Battletech for sale thread hasn't been updated for over a year
Ah, okay, that's the problem. That thread is not active and I'd been meaning to ask the mods to remove it for awhile now. The reason is, I've been trying to standardize a system where each New Release gets its own discussion thread, which is stickied for some reasonable amount of time, or while discussion on the product is still happening. The problem with the "For Sale" thread is that it doesn't allow customer feedback.
For this upcoming cycle of mini-PDFs, I'll probably just create one New Release thread for all of them, and announce new releases there, here, and on social media. That way I'm not generating a new New Release thread every week.
drivethrurpg.com is a good source for purchasing Battletech and I believe they have new releases almost immediately.
Yes, but a very bad source for the big-picture profitability of these products. If that's where you feel best about buying your product, by all means, use that source. It's on CGL to create a web store that will win back your support. It's not something I can directly affect, unfortunately.