As I said above duo will always remain more popular because it's pocketable & if it succeeds it will pull way more sales than neo.
As for neo I see it as a laptop first device. It's a new era laptop/2 in 1 & That's the best way Microsoft can sell it imo.It will sale just like other premium laptops not like phones meaning way less numbers in volume compared to phones.
Neo may not get much developer support but it will function well as 2 in 1. It can surely be category defining device when other oem's launch their dual screen designs eg. Asus project precog.
Regarding software taking advantage of this form factor it all depends on Microsoft's efforts in making this category of devices successful & bring change in industry.
General pc users don't care about store & I don't think it situation is going to Change at all for lot more years ahead.
I think future iteration of duo will be evolve into galaxy f like device when corning launches bendable glass.
But neo will remain as it is (dual screen) with multiple screen size options
I tend to think the exact opposite. PC has high margin development, so vastly more motive to build specialised software, and in addition, the dual screen format for windows 10x is licensable, so third party OEMs can replicate the machine.
Android by comparison is populated by low margin software, built entirely around volume sales, and writing specialised software for it, is almost pointless. If google licenses a dual screened set-up to other phone makers, it also seems unlikely they'll be able to make anything with the elegance of that hinge, and without it, there's not as many possibilities and variations that work for a smaller device.
That said, it seems quite likely to me that folding screens will be a market trainwreck, both in terms of durability, and pricepoint, and perhaps the Duo will be the only one left standing, in which case it might do very well.
What foldables need to do, at this early point is do what the first mobile phones did, or what the hololens is doing - find rich users with a niche application to throw money at it, so it can be built out, and while the manufacturing processes mature. It's not at all clear most foldables are doing this, instead relying on novelty hype, which IMO, only works up until 1k USD at the most. You get to above 2k like the galaxy fold, and what you have doesn't fund it's own future iterations.
But I wouldn't even begin to buy into the notion that high end, specialised folding phones will sell like midrange and price point propositions do currently, and given laptops, including hybrids are the fastest selling kind of PC, I wouldn't stake money on one catergory being higher than the other just yet.
If I were to pick one, though, I'd pick the hybrid laptop - it has a clear, and familiar use case. There may well be a high price point use case for a multi-tasking phone, but it's novel. As for a tablet seamless design - yes it has a use case, but not generally associated with the level of money it's asking for.
IMO, the biggest issue for microsoft, is they have two similar devices, and if they don't share some kind of app platform, that could spell trouble for both of them. That they have two devices with similar design could be a huge strength - in that each could feed into the other. But if they are disperate app platforms, and difficult to write for both, it will drain from both.
They need to have a shared app language.