I have to disagree with you.
Nirvana was both incredibly popular and incredibly well respected at the time of Kurt's death. This wasn't a case of the celebrity death creating the hype - the hype was already there.
At that point, they'd had five good years of music making behind them, two of which were as well-liked indie band and three of which were as biggest-band-in-the-world, but all of the albums they recorded in this time period were at least above average and at most excellent.
In fact, the last major project they released while Kurt was alive - the Unplugged in New York set - was one of their best albums (my personal favorite).
Yes, it's really hard to think what might have happened if more albums were released - but I think the foundation was there for a very promising legacy.
Actually, if you look at the sales, Kurts death was what put Nirvana into the mainstream.. Yes, they were successful before that, but they were not the household name they became AD.. I think that's actually a fairly common occurrence- that being bands popularity takes off after the death of a key member.. They had their core fans, and they certainly had enough of them to be considered successful, but the "fringe" fans (for lack of a better word) never even heard of Nirvana until the suicide.. And there's a heck of a lot more of those "fringe" fans than the core ones.. Now, I know everyone will say "statistics to back that up" , and I agree- so I offer record sales.. Their sales went through the roof.. Soon people who never even heard of them were walking around wearing t-shirts with the baby swimming (or, drowning I suppose)..
The Un-Plugged thing was great, but that was actually going to be shelved because the execs thought there was no market for Nirvana unplugged.. That's why even though it was recorded just a couple months before Kurts death it wasn't released for quite awhile after that.. Their rise to mainstream wasn't immediately after the death.. It was more like a slow burn..
Hey, I'm no expert on Nirvana, and that's just my take on it- I could be wrong, but as someone who followed the band a little bit before Cobains death, I view the band as wildly more popular in death than they were in life..
A couple bands that were mentioned already - one I agree with and one I disagree with..
Agree: Rolling Stones.. I've seen them live more times than I care to admit- hey, what can I say? They're overrated, so when they come to town it's the thing to do.. Worst live band I've ever seen- not even close.. They can't even play in tune, that's the truth- literally can not carry a tune.. Jagger can't remember the lyrics, let alone sing them on time and in the correct pitch, and the very understated ronnie wood blows keith Richards (whom I'm actually a huge fan of) off the stage every time..
Disagree: Pearl Jam.. I'm not even a Pearl Jam fan- in fact I can't stand Eddie Vedder.. But as musicians these guys are great.. Eddie Vedder is actually a great singer, and Jeff Ament is one of the best song writers I've ever seen..
I put a lot of weight into how a band performs live- it's not everything, but it does mean a lot to me.. Anyone can get into a studio and produce something so much that it sounds good- but when a band stands up there and is able to nail it live- time after time- they're pretty good.. Like I said, I'm not even a Pearl Jam fan, but evry time they come to town I go see them because they are so tight on stage..
That's just my opinion though..