There are "traditional" railway modellers who "scratchbuild" everything in their layouts.... equally, there are traditional railway modellers who prefer to use commercially-available kits to produce equally excellent layouts.
Personally, I would liken BVE developers to the scratchbuilders, and M$T$ers to the commercial kit-users...
This is not to denegrate the work of either.... for me, it just clarifies the difference....
If Mackoy was ever to allow commercial development of add-ons, it would simply move part of the community from one camp into the other....
(Yes, I know my analogy ignores those scratchbuilders who either build to order or later sell their layouts; but they aren't using other people's work without permission, which would be the case if someone attempted to sell BVE at the moment).
So, we might as well keep it all free...
With regard to developers and deadlines, we've got to realise that, at the end of the day, BVE is just a hobby. Yes, I would love to have the entire UK rail network modelled to the highest possible standard, but it's never going to happen, whether BVE is paid for or not. As someone who's only been involved in route developing for a year, I've come to realise that BVE modelling improves with practice, but practice takes time. So, my philosophy is, I publish deadlines for myself, but I try to set deadlines that I can keep; I don't make public details about routes I may build at some point in the future, only routes that I am building; I share some of my BVE objects via my website, because I think that a library of objects can help the developer community (and hence route availability) to grow, but I encourage the development of new objects, because variety is the spice of BVE; and I respect all route developers, regardless of the quality of their work, because we all have to start somewhere, and we can all encourage each other to improve our skills over time....
Regards
eezypeazy