Although a 10-lane, 25m pool will address some of the immediate need for additional lap pool space, such a facility has constraints that limit its value for the millions in cost of construction.
Scheduling in a 25m pool does not allow simultaneous multiple aquatic activities.  The current Harry Jerome schedule only provides 16.4% ‘drop-in’ access for the general public, as the remainder of the time is rentals and lessons.  A new 10-lane, 25m pool will be similarly constrained.  This affects accessibility and programming options available to the public.
A 50m pool has the flexibility to run other activities simultaneously, has the ability to host all aquatic sports (not just lap swimming), has a much broader appeal for the general public, and addresses the shortcomings of a 25m pool identified above.  It will satisfy the needs of the public for the lifetime of the pool (next 50 years).