Yoshi-P's concern was that if he dragged out the Ascian/Garlean plot for too long it would become stale and people would believe it's never going to be resolved.
It did feel that way for a long time but we were still excited for a Garlean expansion in Stormblood. Shadowbringers put a big dent in that by distracting us from the Garleans and then making them irrelevant by saying "they were just an Ascian creation". Rebuilding the excitement for a Garlean expansion was rough but Bozja and the weapon trial series did a good job of it.
Obviously, they ruined the possibility of a Garlean expansion but I saw it as an interesting subverting of expectations. Given the amount of people that express this sentiment, they were successful at that.
If you haven't done all of the role quests, then I suggest doing that because Garlemald is involved and it's possible it was involved enough that they won't return to it in the MSQ.