Honesty. At this point, people are using every possible reason to make Boruto seem like the worst crap that ever existed. Of course, Sasuke got stabbed by Boruto. On top of having most of his energy already spent after using spacetime ninjutsu so many times, and getting physically wounded to such a degree, Momoshiki once again possessed Boruto's body, increasing his physical abilities even more. Now, who do you think wins, Sasuke, who's on the verge of collapse, or Boruto, who got knocked out early and much more energy to spare? Even if you argue this reason itself is not justifiable to lose the Rinnegan, sure. However, what you guys are missing is the power scaling of the characters. After Naruto became the hokage, I very much doubt he was able to get much stronger due to all his work. You can't just argue that since he's been able to beat the past Otsutsuki, he should've been able to wipe the floor with Isshiki and company. Honestly, after series like Dragonball, I can't believe people still think that the characters can just keep on defeating others without any prior training.