Yeah, once they got to the point they made images good enough to see a wok or colander suspended from a string from a flying saucer the became rare.
But for those old, low resolution, b/w sensors: yeah, they had some things going for them in terms of actual sensitivity. Cramming more pixels on a smaller ccd/cmos chip doesn't really improve image quality that much and decreases light sensitivity.
I think the megapixel hype has ended quite some time ago though, apart from marketing towards people that have no clue on how photography works. It seems that Canon for example have settled on 20-25 megapixels even for their professional DSLRs. They do offer 50 megapixel sensors, but not necessarily on the very best of their bodies.
I suppose the point has been reached where more pixels stop adding any image quality overall - improvement in lenses give you much more return on investment, even if you take photo's you intent to print on A0 sized poster formats.
Yeah, theres a couple cameras I know of that go up to like 42 megapixels or something, but I think thats so you can crop in digitally without losing quality.
One of the best low light cameras right now is the Sony A7SII, and I believe part of its good low light sensitivty is because its a full 35mm sensor but only 12 megapixels, so you get bigger pixels that can get more light.