Your giving up way too easy. Here is what you can do. Get yourself some thin super glue some 400 and 600 grit wet /dry sandpaper and some exam gloves. In a well ventilated area with the gloves on run a bead of glue along the crack and while it is still wet sand over it with the 400 grit. It will be kind of messy but the glue should wick into the crack and the sanding dust should fill in any voids. Do it a couple of times if necessary and when it has cured finish it by sanding with the 600 grit.
In Italy, when someone who has died has led an admirable life, they clap and cheer at the funeral, as if the person had won a race or a contest because that is how they look at it. Here too, we can admire and applaud the life this brush has led. How many synthetics are going to be kicking around 80 years from now still giving pleasurable shaves? I say give it an honorable funeral and send it off with a salute!
I prefer badger over synthetic, boar, horse, etc. And as this was one of my first ever brushes, I'd rather not give it a funeral.
I know you guys may have forgotten this post or maybe thought I gave up on @IAmTheJody Hardright shaving brush ........ You guys are so silly. Though on a serious note, what should have been an easy repair turned in to a real challenge. There was a time or two that salvaging the knot may be the best course of action. I'll go in to the details in my complete write up on my thread; I'll be writing that in the next day or two ...... stay tune.
It was one of the deals I'd put on a beautiful coat of finish then come back in the morning and see it all turn to nastiness. .......... So I had to get reeeeeal inventive.