The first paragraph seems to imply that they played this lottery for 6 until they (I guess) changed the rules in 2018.

Ah yes. I have a tendency of skipping the first paragraph to get to the meat of the story. Thanks for pointing it out!

He implied the buy-in was about 21k for one attempt with about 5-7% chance of winning. Mocking up some quick analysis for a blog is one thing, taking out a loan for 100k+ is quite another...

You can also split the cost of the 21k across many people. You walk away with less money if you win but you also get a chance to play without selling a kidney. The hard part wouldn't be the finding a fraction of the 21k but finding enough people that would agree on the subset of 20 matches from the overall 38 that you should bet on. Depending on what matches they have listed for the week, you might even play a smaller subset than 20. If most of the matches are strong teams vs weak teams, you stand a better chance than many evenly matched teams. Although his data seems to suggest that splitting winnings somehow results in even less winnings than you would normally think so it really does seem to be that high buy-in is the best course of action.

The guy was a trader in Singapore, odds are he didn't need a loan to spend 21k.

The title of the article reads "How one winner used math to overcome the odds"

He also asked the question about citizenship to play the lottery which he never answered in this case. I wonder if at the least he was flying to Australia to purchase tickets.

The model was in production for 6 years. The lottery has been discontinued, so is no longer viable