1) The translation is correct. "The company is bankrupt" would be 会社はつぶれている。

2) I guess it's a question of naturalness. You said "There doesn't seem to be improvements being done" and she said "It seems it isn't being improved". While one might be more natural in one language, the other may be more natural in the other.

You need to watch out for もの, it has a wide range of usages including some grammar 'set phrases'; "thing" is often not the best choice. The grammar reference I have here splits it into 30 subheadings over ten pages. (a large part of JLPT2 grammar is I think sorting out the various possible もの、こと and わけ constructions...)

I think that for 会社はつぶれるものだ "A company is a thing that can go bankrupt" is a bit too  直訳 -- for learning purposes I'd rather have an SRS-card answer which had a brief note about the grammar than a 'translation' which just reinforced the もの=thing link. It's not that "...is a thing that..." is wrong as such, I just think you're better off going directly from "XはYものだ" to "Y is a general property of objects of type X" without going via the direct translation of もの to "thing". (Feel free to think about it that way if it helps convince your brain it makes sense long enough for it to sink in -- I'm pretty sure I did at first. I'm just recommending against putting it in your SRS.) It's like the idea of the particle は and "as for" being kind of equivalent -- a useful idea, but don't hold onto it too long.

(If you actually want more natural English phrasing of the idea then I'd be tempted by "Companies do go bankrupt" or "Companies can and do go bust".)