I've been wondering about this myself. 

As you can see from my link below. Some horse haven't made any money of the modeling job.

https://horsefable.com/estate/herd-management/career

That takes me to my herd management page, thank you though because now I notice a discrepancy (seemingly?) with my horses.  On the individual horse pages for my careers, they all make money when I seen them on model jobs and gain points.  Using My horse https://horsefable.com/horse/2125277 as an example, under her career section in the history tab it shows me this table below, but in herd management it still lists her earnings as $0.  Same for Rain Or Shine and Shiny Summer Day.

You can see she does earn for her career work. I think I know what's happening though, it's only counting show earnings there.  My horses Painted Desert Sky and Clear Horizons both show earnings in the herd management pages and have previously been shown in disciplines.  So despite being a career tab, it's not counting the money they earn doing the career work.  So that's interesting.

https://horsefable.com/estate/overview ← this should show you earnings from Careers too, so not just Disciplines and Halters. So, just looking in the wrong place for that.

Thank you @TheDustyAngel I found that today too.  However I still don't know how to find which personality type matches which career.  I can see that specific horses of mine earn more or less in the model career but I don't see a way to know which careers they'd be better suited for if they aren't earning the best.  I feel lilike I must be overlooking it, the wiki seems to have had a link at one time or at least intended to have had one based on the career article.

Hey Meriweather,  for starters happy late welcome to the game!    The wiki is currently in the process of being updated and overhauled (thats why some pages look and feel different than others, some may be missing links or info, some may say under construction, etc).    On another note though, at least as long as I have played, personalities and which careers they have been connected to has never been an outright given portion of information by the game (there are a lot of mechanics players are meant to find out on their own, or through the community / other players).    If you could link me the page in the wiki you found that possible broken link on I can pass it along so we can get it updated sooner than later!    

I wish I could help answer the question itself of which personalities go to which careers, but I myself dont know and haven't had the time I wish I could to sit down and mass test it (its been a back burner project of mine for a while now).    As far as I know I haven't seen anyone openly say they have figured it out or share results.   I know a large majority of players only use the model career and save the acres for things like more stalls while some players (like myself) just use the other careers for fun, or they tie it to certain disciplines / breeds, or as I do - using them to break up my horses into smaller career batches (helps me keep better track of them).   For those that do use other careers and are more picky in how they choose them, they usually use Skills / PS / or a combo of both to pick careers.  destinysWalrus has a good Google Spreadsheet that helps players figure out which careers are best suited to the horses Skills or PS, even a tab for careers based on Disc.