You forgot advertising/marketing costs John M.
To quote Bill Gates; "If I only had $5 left in the world,
then I would spend it on marketing".
Fixed costs only .Advertising wages promotions would be discretionary spending .First you need to identify how much it costs to just engage the system .As I said how many jobs to break even .Then drivers will know based on the amount of drivers signing up how many jobs they would each have to commit to in order to make the idea viable or how little work might be available if the amount of drivers are oversubscribed .By having a realistic operational figure you can then decide if you need to limit the initial intake of drivers with a waiting list that will allow drivers join in pro rata .Will there be a committment from drivers to cover all job offers as they are owner operaters .Co Op are a bit like communism where they are run for the Common Good as long as the other fells does more than you do but you get the same reward .Metaxi have this Game sewn up due to the tens of Millions drivers contributed to establishing it .FLAG have the fairest system but have no funds to attract drivers or passengers .I would suggest a 4 Million Euro budget would be needed just to have a chance not withstanding any retalliation from Metaxi .If I was to advise a driver on the most effective option I would suggest become a Mytaxi Ambassador ,they have the work simple as .
I don't think waiting lists are a good idea, in my experience drivers can be offended by that. What ever operation you start it should be able to manage any amount of drivers. As for a lack of work in this scenario, members on joining will be told other than the once off admin fee it will cost them nothing until they work. Drivers that do more will benefit by paying less commission as they move on a volume based scale. The ownership and shareholding are completely separate to the work.
I have spoken to a few Irish App development companies and they appear to speak the same language with regard to costs.
Wireframe to MPV (Minimum Viable Product) for 2 apps (Customer and Driver) on Android and Apple with Back End Admin functions and data storage would cost approx €15,000 to come up with a basic functional prototype.
This could rise to €50,000 in time as you add functionality and a maintenance contract can be negotiated or additional ad-hoc hours may be facilitated at an agreed hourly rate.
The biggest cost will be promotion and marketing. Although you would expect the members to be the best promoters and marketers with passengers in-car, handout literature and talk about the app and when all apps are busy cover the co-op work first. That would reduce the marketing to seasonal campaigns and no need for driver incentives as they own the app. Done right it would put other apps under pressure to spend more.