ultima havent got a strong local player base, which means they need to recruit farely heavily to be a top side. it is obviously hard to do that every year so thats why they find themselves at the wrong end of the ladder. sides like murrabit, wandella, and nully all have strong local representation which allows them to still be competitive in their leaner years. thats what i reckon anyway.
Also dont forget about 9 years ago Ultima went through a period of about 3 or 4 years without an Under 17 side. Any young locals that were left needed to go elsewhere to play. So they lost a few in that period added to the going away for work/uni thing as well. Not to mention good players who have played for the roos in juniors that have for various reasons at different stages moved to other clubs. Luke and Matt O'Toole, Marcus Nalder, and Lance Brown all played together in the minis (at a young age) one year at the roos