I wish this project well. I hope it improves compatibility with BSDs for more projects.
Even at the time, few games used an API where they managed multiple channels directly; Software mixing was commonplace from the 90s. Any game that wanted to play battle sounds was not relying on the mere 6-8 channels that cards from that time could handle.
Our modern Pipewire based workflow is remarkably simple and remarkably effective, and it's significantly an evolution of PA.
And I don't recall a lot of software working well when Pulse isn't available, so I don't know why people still bring it up. Perhaps it's because I wasn't there at the time, but I've only seen ALSA as "that audio system you use when you have nothing else available". I still need the PulseAudio-wrapper for Pipewire to be useful for my systems, so clearly the Linux world has moved to Pulse-first.
But yeah, BSD is not Linux. So obviously things are going to be different. For example for plug & play it has its own devd for USB devices, and it can be configured easily.
If you'd port over all the Linuxisms like dbus, systemd, cgroups etc, then you basically end up with... Linux. What is the point in running BSD then?
It's a bit akin to people saying that every Linux should be more standardised (e.g. standard package manager, standard desktop), otherwise "the year of linux on the desktop" will never happen. But all these quirky desktops and distros are there because people have different needs and they don't want those to be watered down. The ecosystem as a whole doesn't matter to them. The same thing goes for BSD. I'm not using an OS with a desktop marketshare of literally 0.01% because I care about it becoming a mainstream desktop :) I also super duper hate the ideology behind GNOME so I would never use that, if it were the only option then I would just have to leave.
PS: I have no issue with things like dbus being available in ports but definitely not in the core system.