Doesn't mean you don't attempt to find out WTF happened, it just means you grab several dozen random people, program them appropriately, give them old tech that is chakra-locked to only be usable by them and is set to self-destruct on being scanned, dump them on planet, and either get response(s) that shed some light on the issue, or not.
And either way, nothing of value is lost.
Except it's in an area that's considered fringe territory for the Ōtsutsuki, and for basically the entirety of his POV he's outright stating that they're spread wayyy too thin. He's already had to dismiss several other alerts from Kaguya's area
because of these facts, and he's made the assumption (a wrong one) based on the fact that the Power Node network is so active that she's actively fighting whatever is going on in that area.
Meaning that from his POV Kaguya is actively containing whatever is happening in that area, but for him in the here and now he needs to stop whatever is happening to the Reincarnation Network because it's something that's basically irreplaceable to their entire civilization. So for now he deals with that, while Kaguya is the expendable pawn who makes sure whatever the fuck is happening stays away from the rest of the Clan so they can 'ascend to Godhood' and then they'll swoop in to deal with whatever is causing problems.
Plus you do realize the Ōtsutsuki really don't use technology yeah? A lot of their stuff is basically just techniques or stuff made using Creation of All Things.
If they're that resource crunched, then WTF are they doing still attempting immortality?
Immortality doesn't necessarily (or often) come with invulnerability, after all.
They are already immortal, in that if you kill an Ōtsutsuki you get marked with their Kama/Mark and they slowly possess your body and take you over. Or some poor sod gets randomly chosen to be their new vessel. What they're trying to do is become Gods, not immortal... they've
already done that.
And the reason they're so spread out is because it takes
a lot of power to 'become Gods' so they collected the seeds of the Shinju on their Homeworld and started plopping them down on other worlds to harvest those worlds Nature Chakra, upon which the tree will produce a Chakra fruit which will be consumed and the Ōtsutsuki who watched over the process return to the Homeworld and hand over the gathered Chakra to the Shinju on their Homeworld. Basically they're harvesting
entire worlds for enough Chakra so the entirety of their people can
become Gods.
