The good news is, you're not deindexed.
Looking at the site through ahrefs, it appears all but two of the backinks to that page are nofollow. Good job on the wiki link ;-)
Your top anchor phrase is: best 130+ flea markets in america (usa)
You rank number one for that anchor phase. Ahrefs shows it's 39% of your backlink anchor phrase.
For the phrases you are trying to rank, as given in the list above, none of those phrases are used as backlink anchors.
Looks like you may have done some sort of link package in December of last year. It shows between middle of December and January of this year, you gained almost 600 links. Links peaked on January 6 and almost immediately started dropping off. Between January 6th and the end of April, the page lost almost all of those links.
In May, there was a huge drop off in organic traffic that went from May to July, by which time the site was back down to the number of links it had before the link package.
Recommendations:
You have a lot of H2 tags on the page. Nothing wrong with that. Incorporate the keyword phrases you list in your first post, into those H2 tags. For example, you have "Flea markets in NYC" as a word you were tracking, but there's only one mention of "NYC" in the content. For that section, add "Flea markets in NYC" into the H2 tag. You don't necessarily have to replace these, but add the phrases to the H2 tags.
Next, either use the same package you used before...knowing that it's only going to last for a few months at most, or focus on getting some web 2.0 properties and vary your anchor texts a little more using the anchor texts for the keyword phrases you used above.
Having been through things like this myself, over the years, having access to tools to give an inside look at what's happened over a period of time really helps.
Another option is to buy relevant guest posts. Not necessarily from PBNs. On Fiverr (not always the best place to buy, unless you know what you are looking for), you can find guest posts from people who have publishing accounts on very large high profile blogs. If you provide the article, you can published on those high DA/PA sites for $10.
Bottom line: It appears a link package was used, and it gave you some good results. The links from that package were short lived and fell off rather fast over a period of months, until the page lost it's authority to rank well for those terms.
If it were me, I would create 10 or so really good quality web 2.0s with excellent (not spun) content, then start adding some packages to those web 2.0s to trickled down to your site. It will take longer, but should provide longer term results. The other benefit of this, is you now have 10 sites you can work on, to get into the top 10 on google, and push out your competition. Or, for short term, find comparable package to throw at your site again to get the boost going, then start on your web 2.0s.
Hope that helps.