As frustrating as it can be not to get it (with only the first kill each day being boosted), if they upped the drop chance on all attempts (or even just the first) wouldn’t that only cause greater frustration to not get it?
Even if it was upped to a 95% drop chance, there will always be outliers. Personally I wouldn’t want to be that unlucky sod who, after 600 attempts at a 95% drop chance still came out empty-handed after 2 weeks.