If btc has another huge rally though at some point all the new money coming in starts to trickly down to alts and they become very profitable again.
This is my experience from last time as well as my interpretation of the graphs.
As for DOGE I think it's a little overpriced, but at the same time it's built on a community that is highly emotionally invested in it and that is not a small thing.
I would actually say that DOGE would survive a 51% attack much better than LTC for example because LTC is full of investors who will throw it away if it stops performing, there's so many other options.
The DOGE community will stick with it no matter what happens, DOGE will never win, but it kind of can't lose either because it's not really competing like all the other coins.
And in some weird way that makes it strong it it's own right.
I think Doge can win if it is still relevant 1 year from now when only inflationary mining is happening. i just am not sure it will survive
But how would it die?
No altcoin that's on major exchanges will EVER die, even if the devs abandon it, other people will take over and fork it. The most obscure shitcoins from a year ago are still going strong.