@Audettey because we're not saturated with yuri stories
at all, much less those of legitimate relationships. And it's not like asking for that is somehow limiting. That's saying "romance" is limiting. Find me like three het shoujo manga right now that ends with "and then they moved their separate ways never confessing (lol)."
We've had approximately a century's worth of yuri stories based on subtextual, de-legitimizing S-class roots. The new authors growing up on subtext are
finally breaking barriers and writing actual relationships (blurring the distinction between them and the more underground, so-called "real" lesbian literature). Hardly a big ask for this highly positive trend to continue. Take this oneshot. What does it gain by stopping halfway? Make people more sad? Refuse to get to the obvious? Portray, for the millionth time, the delicate transience of (female) youthful passion?
As for isekai, that is squarely on bad authors. The broad premises are ridiculously open. Time machines have been invented and reinvented, people have been falling off the cracks of Connecticut, and meek schoolgirls have risen through adversity to become mighty queens of mystical kingdoms since mass fiction was a thing. Those hacks just can't stop rewriting depraved slave harem-obsessed Dragon Quest fanfiction for some reason.
