Doesn't seem right, the PS app is still showing 0.1% for that trophy. In reality it's going to be orders of magnitude lower than that even, I just assume it's the lowest possible non-zero value they can show. It's such an absurdly improbable event without any sort of hacking/cheating/exploiting (if that's even possible).
Doing some excel based maths
If the top players have a 1/10 chance of winning a match (getting through all the early rounds, and winning the final round), I simulated 1000 "top players" having played 100 rounds. Only one player had managed to get 5 in a row within that 100 rounds.
I then repeated the spreadsheet for the "top players" having a 1/5 chance of winning a match. 26/1000 "top players" had won 5 in a row within that 100 rounds
I then repeated the spreadsheet for the "top players" having a 3/10 chance of winning a match. 137/1000 "top players" had won 5 in a row withing that 100 rounds.
I then repeated the spreadsheet for the players having a 1/60 chance of winning a match, i.e. the approximate chance of it being completely random. But I did it 10,000 times, not 1,000. No one had won 5 in a row after 100 matches.
But the takeaway is this
If 1 in 100 players are a "top player", and the "top players" have a 3/10 chance of winning any match, and on average the "top players" will have played 100 matches each... then based on that, they themselves will have done enough to make it a 0.01% trophy win.
But not a 0.1%