Yup, it generally takes time and multiple campouts to complete these requirements. The overall goal of the requirements is for the scouts to gain experience with the various parts of campcraft: selecting sites, knots, pitching tents, cooking and cleaning…
Advancement is only one of the methods of Scouting. It also should not be a race, despite the fact that the BSA has an age limit of 18 (with some limited exceptions). I’d rather see a youth who joined at 16 (for whatever reason) enjoy his or her time in scouting than just racing through to try to get to Eagle.
The requirements are pretty clear about the campouts and cooking being at scouting events, I believe. Scouts are asked to explain the importance of preparing and eating meals as a patrol; to cook at least one of the meals on “the” campout (implicitly the minimum one campout mentioned in Tenderfoot 1b). First Class 2a explicitly references creating a menu “for one of the above campouts” (which can only refer to the campouts in 1a) , then later requires budgeting, shopping and cooking based on the menu the scout prepared.
Honestly, we generally let the scouts work out who needs to satisfy which requirements, and how to get that done within the patrols. We had one patrol split itself in half for a couple of meals to fit everybody in. They just cycled through the stove.
Executive Chef Scout 1 and Sous Chef Scout 2 each planned menus, then switched jobs for their meals. The Executive Chef role took care of Second Class cooking requirements (only need to plan and supervise one meal), and the Sous Chef role took care of the Tenderfoot cooking requirement. In just two meals, you can get two scouts complete on those requirements. You can knock out eight scouts for Tenderfoot and Second Class in a single overnight, even without splitting the patrols. If you have two nights, you can squeeze in dinner Friday night, three meals on Saturday, and breakfast on Sunday, if you don’t mind starting early enough to let the stove cool down while you break camp. That fits in a breakfast opportunity that would take care of four more scouts for either Tenderfoot (assist) or Second Class (lead) with four patrols. For the scouts working toward First Class, they can get in planning and executing one extra dinner and breakfast if they split the patrols and cycle through the stoves. Since only two of the meals planned have to be cooked cooked per First Class 2a, those scouts could also plan sandwiches or other cold foods for the drive home on Sunday to knock out the rest of the requirement.
For scouts working on First Class, they have to plan, supervise and execute an entire day of meals, but splitting the patrol up let the Second-headed-for-First Class scouts get their requirements covered while letting the other guys knock off theirs at the same time.
It was an innovative approach, and once one patrol thought of it, the other scouts quickly followed suit. I probably wouldn’t have thought of their solution, but they saw a challenge and worked out a solution.