First off, my apologies in delaying a reply. Secondly, no offence taken, the maxim "Trust, but verify" is a great one for these times
My points were based in fact. The 'Flu' jab that you, I or others might receive each season is a 'best guess' of the strain that will be the main version in that year's season. Scientists incubate the strains, then kill them and effectively inject the dead version into the patient to allow the body to recognise it as a virus and then build antibodies against it. It's a best guess, which is why in some seasons, we have a 'flare' because it's a different strain that dominates. It's a bit of a bugger's muddle. See here for a concise but informative way on how they choose (https://www.cdc.gov/flu/prevent/vaccine-selection.htm)
TLDR; It's regional, so a Flu jab in the US will be different to the one in the UK, to the one in Japan.. and so on. And they have to do it 6 months in advance!
To draw comparison with your link (very good btw), the virus has mutated 3 points from the origin - and that's just in that patient, so how many more times might it be mutated before we get to the point of being able to create a viable vaccine that as you say, covers many different mutations - the answer is I/we do not know. We need a lot more cases before we can be confident that that one vaccine will work against multiple strains.
[side note] Not sure if you caught it, but an important point in the UK PM's update today was that secondary testing (those that have caught and beaten the virus) is now key because it will tell us: the infection rate; the survival rate; the amount of ppl that needed treatment vs how many could self-isolate... and will provide many more samples for testing against mutated strains. South Korea and Hong Kong took a very different approach to minimise the spread at the beginning of when they thought an infection may be coming. Both _could_ be valid and viable ways to deal with this threat and will be picked over in the years to come.
With regards to the mutations, the problem we have is that pretty much all of the countries infected thus far have said that no vaccine is going to be available for at least a year - possibly 18 months depending upon how rigorous the testing is going to be. So, you are right that eventually ( I hope) there will be a vaccine, but not in the short to mid-term and that means mutations may have a significant part of play come this Autumn/Winter, especially to those that have self-isolated and managed to avoid the original strain. The one exception is the US who claim to be near to getting a vaccine (well Trump says so!), but I personally think this is more for political purposes than what will actually happen, especially given their previous mistakes in having a diagnostic test that failed miserably earlier this year.
With regards to China especially. It is now very clear that they did too little too late, China had reports in November `19 and sat on them thinking they could contain their first wave - information for any second wave will be vital, but I would venture that it is not looking too promising for the Chinese authorities to be forthcoming on that. For Italy, it is perhaps a case of being unprepared and then trying to minimise spread 'once the horse has bolted'. I very much agree with you that a one-size does not fit all in this case, which is why although Europe is closing it's borders, but the messages coming out from each country are slightly different - some are enforcing shut-downs, others are recommending (appearing to be less authoritarian). The makeup of the population is also very important and perhaps why Italy is seeing more deaths due it having a greater percentage of more mature people, hence a higher death rate that those countries around it. You could also argue that Italy has been the 'canary in the coal mine' for Europe and other countries are now more prepared. The facts on the population makeup are out there for all to see, the time between China's first initial reports and when Wuhan went into lock-down is established, as is there ability to silence discussion around it.
But don't take my word for it, use the most powerful tool that humans have created and find out for yourself instead of posting on FT
Cognoscere nisi habeat fiduciam
Wow an informative, non hysterical post on the Corona virus on foxestalk.