Since B/S, S/G is *often grouped into one group, I would say at least mid/high Gold+ got SQ as well.

You're also very capable of solo carrying in B/S, sometimes G. Gold is the old place where people that did their placements landed (I never ranked ever before S4 or S5 and landed in G5). Meaning, Gold is kind of the tipping point between decent players and casuals, in my opinion. I fell a few divs, admittedly, when I placed G5 and dropped to S3 or 4; I didn't really understand metas and just played whatever. Plat holds players that understand the game but not really the mechanical prowess and sometimes can't really put it to action. There's also a lot of ego problems and boosteds.

But in S5 and S6 I got placed right down into Bronze, for each placement, and crawled myself up, somehow. Specifically for B2, in S5, it took me about 10+ promo trials...But I eventually did it. This was before the promo helper was instated. Promo helper actually helps a lot when climbing out of the gutter and I don't really think that SQ for really-low ELOs is necessary simply because of it.

But by all means, if high gold/plat is connected to B/S/G in some way of 'not skilled enough' or something, make SQ for everyone. Make a separate DQ with a diff ladder (this suggestion is coming next Season, I believe). Since D5 got s/duoQ, it's 100% possible to drop s/duos to the lower elos.

(And you know, fixing the shitty matchmaking for someone when they're doing good..would be nice too.)