Why are brew formulas and casks that outdated?
Brew packages are often quite old and especially casks do not get updates for years.
I have used Arch Linux before and might be spoiled by Pacman and the Arch User Repository. Its really a different story when using brew in comparison to that.
Packages and casks get outdated when no-one is taking the time to update them. That work is done by volunteers.
You could be a volunteer.