It's an interesting question tbh; the idea is they tried doubling XBL Gold to push Gold subs to GP (preferably GPU), and if the conversion rate was as high as they'd of liked, they wouldn't have needed to try doing that.
OTOH, since later in that year both Halo Infinite and Forza Horizon 5 came, and other big games came into GP (MLB The Show, Outriders, Flight Sim (Xbox), Psychonauts 2 etc.), it's possible that more Gold people converted to GPU at that time. Then with the June showcase, in what seemed like set dates for even bigger 1P games (RedFall, Starfield) and 3P exclusives (STALKER 2, Replaced, etc.), there were probably a lot of Gold holdouts who finally decided to convert given the games coming in that Fall and seemingly coming in 2022.
It might be fair to say there's been a high conversion rate of Gold users to GPU. Bigger question now might be, in light of some of these games not releasing yet (indefinitely delayed in the case of stuff like STALKER 2, Atomic Heart and potentially Replaced), Halo Infinite floundering, FH5 relatively soft, the RedFall & Starfield delays, no confirmation (yet) on the next Forza Motorsport coming this year etc., how many of the people who are paying month-to-month, or payed in advance with stacking & $1 conversions, are going to stay subbed?
Because with those who were on Gold last year and maybe decided to then sub (if they could do the 3 years Gold $1 GPU conversion or not, I'm not sure if that's still possible), chances are some of them could drop too but if they locked in with some type of $1 conversion of year-long Gold subs, they can't do that for a while and by the time they can, there might be several Xbox developments making them reconsider that, and staying subscribed after all.