Your odds are actually probably a lot worse than shown here since the rate of fall of certain rune effects is probably much lower than others. Freeze or Greater Spell Pen VIII for example probably have a much lower drop rate than 3.3%.
Meanwhile what do you do with all the dozens of elderich and tempest runes you collect waiting to hit the lottery on the tier III? Of course you can give away your reward, but how long till you just stop running the quest? The game developers have in essence put in place a self destruct mechanism in Mod 8. Over time, the incentives are to not play it.
This system was extremely poorly thought out and designed. The folks making the decision were poorly informed, negligent, or just plain didn't care.