Unreasonable, for sure. I may not be in the several hundreds of tabs open at any given time, but definitely around a hundred. I gave up on Chrome for this specific reason, it'd just kill my battery in no time, whereas I can go an entire work day with Safari and still have battery left for an episode of SV. I routinely have ridiculous amounts of tabs open (for no good reasons) and Safari so far has been the only browser able to cope without draining my battery in no time.
My main reason for ditching Chrome in favor of Safari, aside from the fact that Safari is ridiculously fast, is that Chrome is a memory hog. The way I browse, with so many tabs open and lots of flipping back and forth, Chrome routinely eats around 4gb of memory in total, whereas Safari uses somewhere in the vicinity of 50%-75% of that. (Looking at it right now, it's at 1.86gb.)
I don't think Safari is the perfect browser by any means, but it's the best one I've used so far.