Where should ITAM sit?
I don't think IT Asset Management has a natural home yet - and I don't think it will have one in the short-term. Just talking to people at networking events, and past experience shows that ITAM sits in so many different departments. Sometimes this is down to a 'accident' (aka, the business just puts them to fit in wherever there is space!) or the business specifically putting ITAM into a certain department to align with the overall goals and objectives of the organization.
ITAM doesn't have a home yet, it is a roaming bundle of business intelligence! Quite frankly, this should be the case as it provides support and valuable data to so many business areas. Sitting it in a single unit may restrict its impact.
How should ITAM be resourced?
This all depends on the size of the organization, the technologies available and the overall objectives. Also, I think it depends on what 'ITAM' means to them. Some people still see it as just a compliance function, whilst others see it as purely hardware. I think organizations need a bit more education on what ITAM means - that it is the management of IT Assets throughout their lifecycle - not just compliance!
We've seen a number of posts on here about 'how many ITAM people do I need in my team'. There is no single answer, nor a correct one. It depends on the size and complexity of your organization and the key software vendors that have a presence within the organization. Either way, you certainly need at least one dedicated ITAM professional within your team & some form of inventory, license management/usage and hardware technologies in order to optimize your IT assets.
The future of ITAM? I see the gap between SAM & ITAM shrinking. Hardware assets are migrating from desktops, laptops and servers to mobile devices (I think servers will always be around, unless you move everything to a hosted environment offsite?). Therefore, you need mobile SAM with some organizations not even caring about the physical phone!
Whatever the future holds for our wonderful industry, you can be sure that ITAM professionals and a team will always be needed!