From what I’ve seen and from what I understand of the rules, a linked troop shouldn’t mean “double the volunteers”. The committee can be the same across the two troops, and if they’re running a coordinated program, the actual work for any committee member should only be trivially more.
The only adult-leader position that can’t be shared across two troops is the scoutmaster, and even in that case the SM of one troop could register as an ASM of the other, and vice versa.
There are two girl troops within easy driving-distance of my home: one is a linked troop with the lowest-numbered boy troop in the District (and probably in the Council!), chartered by a nondenominational church; the other is an all-girl troop, newly established as part of the pilot, chartered by a fraternal organization.
My sons’ troop has looked into setting up a linked girl troop. It’s been discussed at committee with no objections to proceeding, and the SPL once introduced a group of girls to the SM who seemed interested in joining a troop run by the BSA program. However, they never showed up to any other meeting, and our SM also reported that he got push-back from the DE, who would rather grow the established girl troops for now.
It also might be the case that your CO is adding additional requirements for the linked-troop that lead to “double the volunteers”, for example if they say that an adult cannot be the only adult of his or her gender at an event. BSA has no rule preventing a married couple, or two adults of one gender and a third of another gender, or even two opposite-gender unrelated adults from serving as the minimum two leaders at an event.
I grant it’s possible that BSA might allow a CO to charter a truly gender-blind troop at some point, either because the CO believes that’s the right thing to do as a result of its own principles, or because the CO is compelled to do that by state law. But it won’t be because the linked-troop model has too much overhead; if done the way the program already allows, that overhead is minimal.