Hi
@Li-Or Amir,
1. I'd use a heuristic of minimum five development teams hosted on the platform to justify the investment in the dedicated platform team. However, it's more nuanced, as you need really benefit from economy of scale.
a.
(average costs of do-it-yourself) x number of teams costs of building and operating the platform - money equivalent of other value-added capabilities
2. Yes, it usually co-exist alongside infra team focusing on the cloud landing zone/networking/compliance layers.
3. I think they always own the production env in terms of underlying infra. With a dedicated SRE capability they can potentially look after applications.
4. Big question of cross-charging model.
5. I'd say platform engineering team is responsible for sticky-glue code mainly and operating this on top of existing managed services provided by Infra team/cloud provider.
I'm happy to jump on the call if you need further advisory in your platform engineering journey.