The MBR partition table supports a "partition size" of 4,294,967,295 sectors. Assuming the standard 512-byte sector, this translates to a total limit of 2,199,023,255,040 bytes = 2TiB, or just under 2.2TB.
Some sources refer to this as a "partition size":
Because partition tables on master boot record (MBR) disks support only partition sizes up to 2TB...
...whereas others refer to it as the total capacity of the volume or disk and insist that it must be formatted as GPT in order to overcome that limitation:
In order for an operating system to fully support storage devices that have capacities that exceed 2 terabytes (2 TB, or 2 trillion bytes), the device must be initialized by using the GUID partition table (GPT) partitioning scheme.
With the above in mind:
Is the 2TiB limit a partition limitation, or a total disk/volume limitation? If it's the former, is it possible to increase the usable space of a disk by creating further partitions less than 2TiB on it? If not, why not?
Given that the 2TiB limitation is based on traditional 512-byte sectors, and that increasing the sector size significantly increases the maximum partition size, why is upgrading to GPT the standard advice for bypassing the limit when the problem could be more easily solved by simply formatting with a higher sector size? Are there reasons this approach isn't adopted instead?
N.B. I've spent a good few hours reading up on the information currently out there, both on and off SU, which means that I've digested most of the top results on Google and have not been able to find answers to these questions on them, which is why I'm asking here. For this reason, I'm aiming to avoid answers that simply cite those results, and am primarily looking for answers from someone with a good understanding of how the technology works.