No this is not reasonable. There are a grand total of 29 S rank hunts in the game as of this time (2 of which can not yet spawn). S rank hunts take about 3 days to respawn after being killed. There is no way to speed up this timer and you are dealing with all the other people on your server to even have a chance to participate in one of these. So if you are lucky you may get a handful of kills each cycle. So we are talking about many years to get anywhere close to 2k S rank kills if you are not on a low population server.