Virtually none of this is true with regards to SBRs (NFA-encumbered items as you put it). You need only remove the short barrel and replace it with a longer one and it's no longer under the purview of the NFA as long as you don't maintain the ability to switch it back.Well, I don't imagine anyone get's married just so they can endure a divorce, regardless of how profitable the split may be. Sometimes though, things don't work out the way we hoped for, so we part ways.
I'm fine if someone else doesn't see the difference between buying to sell, and selling something that was bought; one is a motive, the other a result.
NFA items come with baggage; it can be difficult, expensive, and almost always time-consuming to change one's mind. And, it's not easy to go try them out in advance to say yes or no before committing. Mail-order marriage? Who knows.
Selling a rifle is easy; selling an NFA-encumbered rifle is harder, by definition. But let's say you just want to re-barrel it because you shot it out, now what? Title II weapons come with baggage; incoming and outgoing.
It's worth thinking about acquiring any and all NFA items long term even if you know, or believe you won't need, or want to, part ways with them.
I've spent more on beer than NFA items; right now they are both worth zero; I have no regrets with either of them.
You don't even have to write to the ATF to have it removed, but can for your records and courtesy to the ATF. The rifle can be transferred as any other Title 1 firearm.
There are additional burdens to owning an NFA item (including traveling with SBRs) but transferring them as normal firearms is not one of them.