I would love to see Haiku reach the stage where small businesses would consider it as a desktop OS (at least for cases where their whole business runs on a single application and the users don’t have expectations about word processing suites, etc). First of course there needs to be development tools available with the kind of productivity that other solutions offer on other OSes.
I want to make a comment on multi-user support, though. I don’t think Haiku needs multi-user support built-in to the OS (at least not for a workstation environment) - I think it would be better to have an application which allows a machine to be joined to a Kerberos realm and then a login screen is presented so that a network user can authenticate.
Business machines are normally joined to a domain so that they can be centrally orchestrated - home computers tend not to have such a use case for multi-user support these days. Nearly everyone has a smartphone and personal computers are normally only logged onto by one person. I think it would be cleaner and more forward-thinking to drop the idea of multi-user locally and just go for realm-based authentication. Users’ home directories and preferences could then be shared as on a Windows domain.