I used to know these ratios better when I was reworking staffing, but I’m pretty sure state mandated child:teacher ratios are lower than that for preschool, lower still for toddler care, and something like 4:1 for infant care, and they must be met at all times to function, so you need backup/slack for eg teacher sickness. And in preschool, the teachers typically need non-licensed assistants to help with eg potty accidents that would otherwise pull them away from the main group.
There is also a surprisingly significant administrative burden, so you typically need administrators to handle things like state licensing compliance (including surprise inspections), parent communication, teacher scheduling, billing, payroll and all that entails, cleaners, scheduling and contracts for photographers and activities, new enrollment, tours, marketing efforts, insurance, etc. These are typically older teachers, so they’re not the most technically savvy group, and perhaps less productive when tech is involved than you might think. And parents expect to be able to text them, pay online, etc nowadays, so they have to use some tech. But the upshot is sometimes they can pinch-hit to meet your ratios.
SaaS has gotten surprisingly expensive, too, that was sucking a big hole in our budget when I first started helping out, and while I’ve trimmed it significantly, it’s still surprising how greedy they are compared to eg 5 years ago (looking at you, Gusto). Ditto thinks like online payments with credit cards, had to put a stop to that asap.
The school I help with is a nonprofit, so there are no shareholders, and the building is a little more than 10% of our operating budget, so it’s not landlords. There is no “excess money” for us, but maybe there is in one of the corporate operations.