Guerilla solar will not & cannot take off. Community solar, however, yes. A “power co-op” where communities / towns / neighborhoods can pool power gen, storage, and use. Forming a small grid of their own that sips from the larger grid if needed.
Vampire devices are largely irrelevant, but always worth knowing which of your devices draws power. My 3d printer just sitting, but on, draws 10w. Off, it draws <1w or lower. My unplugged phone charger? Less than 0.1w. Is this larger than 0? Yep, is it enough to matter, no, not really. Being extremely pessimistic, we can say that all powered off devices plugged in vamp about 1w of power. At worst, my whole house would waste about 30wH. Over a day, that’s 720wH. A week is 5kwH, 20kwH/month, 241kwH a year. An average home for my homes size & area uses 12,632 kwh/year.
Now, we put this a slightly more realistic scenario where most unused devices vamp between 0.4-0.1 (avg 0.2w), and 241kwH/yr -> 48kwH/year, or about 0.3% of my average household consumption.
All that said, know what your devices pull. unplug or turn off the that are “big spenders” when idle. I turn off my printer and unplug TVs that rarely get used. Power strips help for things like stereo or home theater systems.