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Per MSDN,
In SQL Server, the page size is 8 KB. This means SQL Server databases
have 128 pages per megabyte.
How do we change the page size, e.g. to 4 KB or 12 KB etc?
Also, is it due to an “innate hardware restriction” that page sizes are chosen to be 8 KB?
Or is 8 KB simply an arbitrary good-enough number chosen based on heuristics for optimization of majority use cases?
Short answer: you cannot change it.
For reason of efficiency of addressing (TLB) and efficiency of IO (see Reading From or Writing To Files Using a Scatter-Gather Scheme) the database page size must be some multiple of the OS page size, which is driven by the platform hardware architecture. x86 architecture has a 4k page size (see the sidebar on x86 Wiki article, or refer to the Intel Software Developer’s Manuals), newer architectures offer large pages and SQL Server leverages them for memory allocations, see SQL Server and Large Pages Explained.
For reasons of database file portability the on-disk file format cannot be changed to accommodate modern CPU larger pages, it would break the capability to read the database on an older hardware. And experience shows that the 1MB page is quite difficult to allocate soon after OS start up, due to physical RAM fragmentation (a processor page must map to a contiguous hardware page). And such a large page would not play well with WAL (See ARIES).