The reason you answers aren't passed from survey router to survey router is multifaceted: one, it's requires more advanced coding on the server; two, it increases the length of time necessary to set up a pass-off; three, market research companies are especially careful to avoid anything that could land them in 'user privacy' related controversies, as such things tend to scare off the big-name clients.
The reason that they sometimes 'wrap around' is that there are substantially more survey takers on a given day than there are matching surveys, so pretty much everyone backs up their own cache of surveys with redirects to OTHER routers with their own cache of surveys.... the idea being that otherwise your "click" on their ad was wasted (i.e. they have no revenue potential vs. redirecting you to another router which pays them for the survey complete, often at higher-than-market rates due to high volume).
At the end of the day your survey experience will depend substantially on outside factors: what time of day it is, what kind of surveys are available, and what your demographics are. This is why some people seem to get credited for daily surveys more often than others: they are often in a statistically 'desirable' demographic because they are otherwise hard to reach. You have to try the surveys for a while and see if it's worth your time. We try to offer a variety of moneymaking possibilities to cater to different tastes.