Yellowstone and Long Valley (Mammoth) tend to take a half million or more years between mega eruptions. Consider the possibility that Toba has not had time to generate the magma to do anything close to what formed its lake. So, maybe we should worry about somewhere else, like New Zealand, or Japan, or Mono Lake (last from Roy Bailey comment from about 1988).

By the way, I rarely comment on posts unless I have something to add or it is a new piece of information to me...I saw a public TV show on the bottleneck due to Toba about a year ago and probably posted about that at some time in the past here. I would be a little doubtful about that hypothesis...it certainly would not have been good for humans or other living things, but to have a global bottleneck of that severity....I have some doubts...Homo Sapiens has survived a lot the last 100 ka.....(for example, full blown ice age).
Chris