Actually that is not correct based on what I found while going over the stats. Pool has by far the largest number of registrars, more than double (if not triple) that of MyID (and others). MyID, fastweb, and sibername have similar number of registrars and this number accordingly has less of an impact.
I agree that Pool has many things going on and so they don't seem to focus much on TBR. Whatever they get is probably due to their sheer number of registrars. It's mostly an automated system almost completely hands off. That's why anytime there is a small change like daytime savings they tank badly.
I believe however that lots of tweaking happens with fastweb, myid, and sibername and it's a brutal game where literally a fraction of a millisecond can make a lot of difference. So luck has a role to play as well.
I also believe that any registrar that knows what it's doing can land in top 3. In the end, only one registrar can be at a certain position in a particular week and who that registrar is has no bearing on how many other registrars that same provider has. They don't have pull power. So I again agree that one has to be both clever and lucky.
That's why observing results over a long period of time is a far better indicator of who is
#1 in this TBR game. Luck factor tends to not be so important when tallying results over a year or so.