Look at the history, I'm surprised so many people are surprised about our performances in this olympics so far.
Australia were winning well under 30 medals before the 96 Olympics, the 96 Olympics saw it go up significantly and then again in 2000 at the home olympics, it went down by a fairly large number in the very next olympics and further still at Beijing.
Look at the Chinese, they used to win sub 30 medals not that long ago it was increasing and in the run up to their home olympics went through the roof. America has since 1900 peaked massively for olympics but more recently you see the numbers coming up the olympics before. When they had them very close to each other LA/Atlanta the numbers didn't go down much in between and even more recently its been fairly stable.
Basically when people start to bid for the olympics the home nations goes into "find every kid who is good at sport in any way and run him to death till he wins something".
In the past it used to be, olympics over, go get a crap job now but in the past 15 years the "pro" nature of athletes and advertising money going through the roof, sponsorship has made athletics so insanely profitable we don't really see such a massive drop off. Athletics has been huge in the UK for a while, we will have pumped WAY more money into it than almost any other nation, we'll peak and then a lot of these guys will stay athletes.
Australia are 12 years on from their olympics, barely anyone involved then still involved(competing wise), the upswing of people taking up athletics after an olympics is well and truly gone.
Spain, 4 medals before Barca, 22 at barca, a general slowing down over the next 15 years and 3 so far here, well and truly back to where they were.
This happens, you have huge spending, investment, coaches, sporting venues built, training facilities built, paying coaches, then a decade later half the training facilities are run down, the coaches have retired, the athlete's don't get funding to train so have jobs and train on the side and it goes down hill, as they do less well, less kids get into athletics.
Look at the numbers for the Melboure olympics mid last century, 1/13/11 medals in the year before, 35 for the year it was in Aussie, the 5 years after were 22/18/17/17/5 medals.
The greeks, who should really care about the olympics, years running up to Athens were 1/2/8/13 then 16 medals in the year they held it. So no where, then a ramp in quality when they know they'll host it, then 4/2 medals in the years following.
Basically expect any country who hosts it to ramp before, peak, then disappear, with only a few ultra sporting nations to stay pretty high all the time, Aussie won't completely disappear, USA never will, Russia/China, we'll probably use this and continue much higher than normal for a pretty long amount of time.
India just suck, they are one of the poorest countries around with more poor people than pretty much any country in the world, the country is in a horrific state, they can't afford to invest in athlete's to "force" them into becoming a nation that could compete. They've never gotten over 3 medals in an olympics, ever, they just don't give a damn about athletics as a nation.
Basically no one is underperforming, very few countries who haven't been a host nation care all that much about it, home nations almost always do significantly better than normal(but see the increase in the previous olympics as well), almost always drop off dramatically after.
