Not to belittle the impact, but I don't think this is "doom". If even 5 feet over normal high tide makes a difference with where you are on the coast, then you are experiencing frequent seasonal flooding, and are almost certainly getting completely devistated every 20-50 years. Coastal people, that near to the waterline, understand that they're on borrowed time. The time between being leveled will definitely decrease, but it's in the cultural memory in these places. It's not going to be doom, because it's not going to be some unforeseen transient in their experience. They're not going to have structures they expect to be there next winter within 4ft of sea level. It'll be more frequent devastation, with a slow, eventual, loss of will to put up with it. But, it will be slow. A 2ft transient isn't going to destroy anything, except areas that get destroyed multiple times a year already.
Yes, this is one of the areas that are flooded seasonally, and devastated every 20-50 years. To put it into perspective, the tidal range in the pacific islands is around 2 feet. Yearly storm surges go from 5 to 20 ft (hurricane required for the upper range). This is why there are surprisingly few buildings at risk [1]. Nobody builds/rebuilds where frequent destruction happens. People are smarter than that. People will slowly move inland, which is unfortunate to those at the perimiter. But I don't think this is "doom".
Without minimizing the seriousness of what it is... "Doomsday"? For two feet of sealevel rise? (And over 80 years, if rsj_hn is correct?) No. Just no. You have way too wimpy an idea of Doomsday.
That's fine and I'm all for new theories and new models, but let's let them actually make it into the IPCC and see how they are peer reviewed, how the findings are reproduced and assessed by other scientists, etc, especially before multiplying current consensus estimates by a factor of 10. Extraordinary claims require extraordinary evidence, and all that.