The same situation with Ancajas because he originally prepared for a title defense fight against Kazuto Ioka but was replaced last minute by Fernando Martinez and Ancajas ultimately lost the title he held for quite a long time. These instances can't be predicted because the original boxer wanted to participate in the fight but an issue surfaced later on which resulted in a need for a substitute just like this time.
Even if there's no sudden replacement, Jerwin Ancajas might probably still lose that supposed original fight.
The reason is very clear and it was stated by his team. Ancajas is not in good shape because of his hard training to catch the required weight. That resulted in him not performing on his usual and Ioka might take that as an advantage.
As I read on some reports, that's the focus now of Ancajas camp as they are really preparing seriously to get a win on a rematch against Martinez.
It's all speculation though, so 50/50. But if you look at some fights that have their opponent replaced, there are fights that the replacement fighter won or not. Not sure what is the statistics though or if there is one in the internet.
Nevertheless for Jerwin and his camp, they should treat it as a learning experience, a learning curve that they need to overcome right now if Jerwin wanted to became a world champion again and chase more like Ioka in the future.
You're right, we can speculate all we want but that will still leaves us to the point where we can't know the answer because the fight didn't happen because of that Covid that's why Ioka had to give the spot for Martinez and ultimately, Ancajas lost the fight because of that sudden change.
Anyway, Jerwin already have some knowledge now how to counter Martinez's punches or even outmatch the latter. Let's just hope too that Jerwin wouldn't experience the same situation he was in their first encounter because I heard that he was struggling to make the required weight.