I understand that she's your wife, but what are her attachments to the country? From what you have posted, it seems that the only positive thing on her profile, as an applicant of a US tourist visa, is that she's married, and being married doesn't guarantee a visa.
To get a tourist visa, you need to look good ON PAPER. It's like a package. We all have negative and positive points, and we need to show is that we have more positive points than negative ones, or that a few key positive ones are stronger.
Also, she's been married for a short period of time, and to a US citizen, with a considerable age difference. To me, those would be red flags. What would stop her from staying in the US if she wanted to? She's not a minor whose parents are responsible for her.
Your former wife got a visa in the early 2000's just because back then there was a different policy than now. Visa criteria often changes from time to time.
I know someone who's married to a US citizen who got a US visa (both living here), but she does have kids and goes to college. So even though it's not that of a common situation, it's not impossible.
I also know a Dominican woman whose husband is a US legal resident (He's Dominican). She's also got a US visa, but she has a good job here and their kids are here and go to school too.