It didn't die when FPGA's came out?
That's cause FPGAs weren't really better. Their only point was lower power consumption, which was a big deal when BTC value was at the bottom and profit margins were small. Now that they've improved, FPGAs aren't that lucrative anymore. They were always more or as expensive as GPUs.
ASICs, on the other hand, improve over GPUs on all fronts. You get far more GH/s per BTC than you do with any other option, and power usage is greatly improved again. So yes, ASICs will kill bitcoin-mining GPUs definitely, but non-SHA256 cryptocurrencies will likely remain an option.
I agree with almost everything you said about ASICs improvements but think they differ from GPU and CPU mining in one aspect: being application specific.
Up until very recently, Bitcoin mining has been driven at a basic level by the ability to get meaningful results on equipment that people already had, or could easily purchase. They could also be used for either computing or graphics and could also be resold for those purposes, typically at a decent resale value.
ASICs by nature of their specificity, completely change that part of the equation. As you mentioned, non-SHA256 cryptos will still be an option, and I think it will be fascinating to see how that difference plays into the relationship between Bitcoin and the other cryptocurrencies as ASICs are introduced.