Plenty of people have been admitted to MS programs without a BS/BA when they prove why they're the exception. Serious private sector work fills in the gaps easily. MBA programs are no different.
That's an oddly specific case. But as I said, digging into the exceptions will always find something to support any point of view. I'm looking at the overall situation. In most cases the degree can be compensated with work experience.
> Plenty of people have been admitted to MS programs without a BS/BA [...]
This of course is entirely up to the program. Most PhD programs require both, some require only one. What I said is that I (personally) see this as a natural progression. Skipping one will have to come with a damn good reason attached. Like exceptional performance otherwise.
> MBA programs are no different.
Again, personal opinion, I trust the MBA program the least of all. I have seen so many people (including a lot of colleagues) dish out several (tens of) thousands of Euros to get an MBA while still in their 20s, with only some mediocre team-leader over 4-5 people for 2 years experience behind them that I simply cannot put any kind of weight in that achievement.
There's a lot of reasons why you wouldn't finish a degree that are valid. Have you considered asking rather than assuming? What if someone had serious depression or social anxiety? You're making a lot of assumptions on being "serious" and it's honestly pretty naive and silly, borderline offensive, and very common in academia.
Pretty sure that's asking, and if you find that _borderline offensive_ then you probably need a little bit thicker skin. If you're applying for a top-tier institution, they are going to look for red flags in your transcript, and not finishing your education, no matter the reason, is a red flag that needs to at least be explored. They aren't going to simply _assume_ you had some legitimate excuse for not finishing because many people don't.
I don't think it's fair for you to call it naive and silly for someone to understand your background. No one is saying that your serious depression or social anxiety isn't a legitimate reason, but it's also something that has to be considered. Academic institutions have a graduation rate to protect, and they aren't keen on letting someone in that is a risk to drop out after a couple of semesters -- no matter the reason.
If depression or social anxiety are holding you back in your life that much, it's time to seek help, by the way. As someone who has experienced the same, that is a really good indication that it has gone past a simple mood thing into a serious medical condition.
Best of luck.