Barring any major changes in how the game is played (which is a little unrealistic I'll admit), there's about a 5% chance DiMaggio's record is broken in the next 100 years. That's extrapolating from
Bill James's calculations of the annual probabilities. For Cy Young I'd guess it's lower than 1% but not
much lower. Imagine this scenario...
A pitcher with peak ability somewhat better than, say, Pedro Martinez also has, via good genes and mechanics and improvements in athletic training, the longevity of Nolan Ryan and is fortunate enough to pitch for a team that, on average across his career, also has the best lineup in his league. Let's say also that his career starts ten years from now when every team has a 2-3 inning starter and a 1 inning closer, and that this guy's job is to pitch innings 3-8 every fifth day or 4-8 every fourth day. He pitches for 25 years and also happens to be a slightly more skilled pitcher than the best ones we've seen so far. Such a pitcher would average better than 20 wins a year (i.e., > 500 career Ws).
The odds that someone will break Hoss Radbourn's single season mark are much lower, and as I've mentioned before, anyone who can somehow win 61 games in a year at some future date stands an excellent chance of winning at least 512 in his career, whereas even a pitcher who somehow ends up with 512 career wins is unlikely to have had any 50 (let alone 60) win seasons.