Why is it that you never see a pop filter attached to a boom pole?
1. As Alcove said, you don't get as close with a boom and
2. A boom mic is never directly in line with the airstream from the talent's mouth, usually the mic on the boom would be well above the talent's mouth, angled down at a tangent to the airstream. This above and angled down approach is occasionally done in studios when recording singers as well, in which case a pop shield may not be necessary.
What All-Star recommended is an unbelievably cheap solution.
The important word in that sentence is "unbelievable"! If you can get all the mics All-Star Productions suggested very close (a few inches) to each of your subjects' mouths there's a slim chance it might work but mounted on the suggested desk stands a couple of feet (or more) almost certainly won't. If the mics are more than a few inches away and out of the direct airstream you probably wouldn't need the suggested pop shields, so it would be even cheaper! However, although I haven't bothered looking them up, almost certainly these mics have a cardioid polar pattern and will pickup sound from the side almost as much as they do from the direction in which they are pointed. Not only will you therefore get a lot of room noise but you'll also get a lot of "spill", other gamers being picked up on all the other mics not pointed at them. That will result in an editing and mixing nightmare, where just eliminating phase issues and getting a very noisy mix would be an achievement!
Some might disagree, but it works.
I'd very much like to hear any example you have of multiple (more than one) subjects and desktop mounted Rockband mics, to understand your definition of "it works".
I have a turtle beach px5 headset that was nearly $200 but if I hook it up to my PC via bluetooth it sounds like I'm talking through a tin can.
AFAIK, the bluetooth protocol does not provide steady or wide enough bandwidth for full quality audio. All the bluetooth systems I'm aware of, data compress the audio stream with very lossy codecs. Usually in this scenario 8 channels of wireless headset lavs would be used but that's going to be pricey! Next best option would be wired headset lavs, still fairly pricey but many times less pricey than wireless. Next down the list of options would be one of Alcove's suggestions.
As Alcove stated to start with, 8 subjects all in relatively close proximity is a challenge. Even with expensive gear operated by pros it would be challenging. Your one potential saving grace is the low quality expectations on Youtube. Whichever budget option you decide on, it would be wise to test it out first with 8 subjects (as difficult as that may be) because there's a fairly high probability of something not working as you expect/hope, either with the audio itself or with the data management of 8 simultaneous USB streams.
G