I don't think the salary difference is that significant. It's often the difference of somebody simply drafting 3 or 4 full-time "extra" bats (for platooning, pinch-hitting and/or defensive replacement). For example, I have $15.5M worth of third basemen (Boggs $7.9M and Santo $7.6M). I am only going to play one at a time. That doesn't mean my team is $7.6M better than the team that doesn't draft two 3B. Some other team could be just as good with a 150-PA platoon/pinch-hitter/defensive replacement at 3B that cost only $1.5M.
Plus, how many people are drafting "extra" innings? In the first version of this theme, I drafted only about 1475 IPs. This time, I am projecting to have around 1750 IPs. Those extra 300 IPs cost about $10M.