I can only speak to the Homegrown location in Redmond, but I'm not surprised it's closing down. The location just doesn't make sense to me there at all - if they were half a mile south there's Amazon and Microsoft offices there that would be close enough for workers to grab lunch. If they went east by a mile there's a business park right there. Yes they are close enough to both that they could still get that foot traffic, but people would also pass by 10 other places on the way they'd stop in instead. They also open at 10 so no way to grab breakfast (or lunch) on the way to work, and close at 6 which is too early for folks coming back from work wanting a small dinner.
There's a park right there, and lots of people hanging out after work are grabbing ice cream from a place that's in the same building - that's the kind of establishment that makes sense in the location they are in (the ice cream place is not a sweat shop either that is only able to survive by underpaying workers: as far as I can tell their starting wages are 21/hr, they have 100% employer paid health insurance premiums, paid vacation and sick time, and a ton of other benefits - Homegrown's benefits were worse despite the union). There's 2 other cafes that have sandwiches nearby, and for one they are open starting at 7am so you can actually have breakfast there before work, two, Homegrown charges 15 for a sandwich which gets you a full meal at both those other places. From a quality standpoint the other 2 also feel more like a proper meal than fast food.
If this is the way that they ran all of their locations, then really there is no surprise here, union or not.