WM's problem isn't hardware related. Hardware is the only thing OEMs bring to the table however. WM's problems are ecosystem, app, and OS related. OEMs can't do anything for WM in any of those areas.
The ecosystem should be stronger than ever right now. With Windows 10 bringing an unprecedented synchronicity to all the forms of the OS, this shouldn't be an issue. In addition to the WaaS model with being able to publish updates as frequently as they would like is pretty damn awesome and impressive.
Apps are struggling, but without a "Official Release" of W10M, I don't think we've seen the last of new apps or apps being made into Universal Apps. Rubino and others have all but seemingly confirmed this. This is also ignoring the fact that you can live without a Kik, Snapchat, and some of the other apps everyone claims W10M so desperately needs.
The OS is no where near as bad as everyone says, especially with the .71 and .107 updates, which are now available to all users. Those two builds fixed a lot of the glaring issues and have brought widespread stability to W10M devices. As I mentioned before, WaaS allows this to happen, imagine if we had to wait for carriers to release the .29, .36, .63, .71, or .107 builds? We'd still be waiting for those updates. Microsoft has done themselves a huge favor by going after this model, this is nothing short of a huge win for them.
Considering the amount of ******** and complaining I've seen about the build quality of the Lumia 950/XL, OEM hardware should be a winner. Long gone are the days of Nokia making software strictly for their phones, so there is no more restriction of having to buy a Nokia to get a good camera app. Had I not bought a 950 XL myself, I would be seriously considering the HP Elite x3 when it launches, I may still be considering that regardless.
As one last comment, the looming Redstone update (and hopefully looming mobile insider builds), we should see some significant changes and improvements to the OS. Between the upcoming official release of Windows 10 Mobile and the subsequent Redstone 1 & 2 updates, it's way too early to consider this a losing OS. Just the improvements since the November launch are reason to have optimism.
Take care all!