I have already admitted up front I'm no expert. However, I think "firmware" is programing stored on the drive Not the motherboard chip set. the motherboard chip set could give a shit less What the OS is telling the Drive to do. It just passes it along via the proper route at the proper time so as not to disrupt the whole system unnecessarily. As far as any other "drivers" they would be software. They would be installed in or part of the OS to tell the OS what, when, and how execute trim and send the command on to the drive. Note this is OS software Intel doesn't have a damned thing to do with it. It's up to the OS author to decide if when and how to incorporate it. The onus is not on Intel to do this it's on the OS writer.
So why again would you design a computer and operating system and install an SSD with out Trim support? And Why would you not incorporate it into your OS. You are the system designer and author of the OS. So its up to you to write the optimal drivers Since you know how your system works and what is optimal for your system. The drive should just be there patiently waiting instructions. And what the hell does Intel have to do with writing Apple's software and drivers.
I don't mean to throw more fuel into the fire, but I think some fact-clearing has to be done here. The above is absolutely correct. Firmware has absolutely nothing to do with chipsets. The chipset simply passes the instruction through to the correct channels (in this case, passing the TRIM command through to the SATA SSD) and has no real role in how TRIM commands are processed or carried out. Now, sometimes there are strange compatibility issues with chipsets (generally an unexpected error due to a tiny flaw in the chipset that only shows through when certain commands are used. This just happens on occasion [remember the AMD TLB bug?] due to the complexity of modern ICs), but this is certainly not the case with Nvidia chipsets. Unless its an Intel SSD, Intel doesn't really have anything to do with the TRIM command- its the OS, the driver, the SSD, and the SSD's firmware.