If you'll notice, memory is often made on a carrier (e.g. SIMM module). So you don't have to find someone to make you a x9 or x34 or whatever bit wide chip; you find someone to make a carrier out of off the shelf parts with enough chips for your word width (possibly burning some bits). Early 9-bit SIMMs had 2 4-bit wide DRAMS and 1 1-bit wide DRAM. Just need a memory controller that makes sense of it.
(I design memory controllers ....) you can sort of do that depending on where your byte boundaries are (and whether your architecture needs to be able to do single byte writes to memory) - more though I was trying to point out that historically just 'burning some bits' was not something you could practically do cost wise (it's why we built a 9/72/81-bit CPU in the 90s rather than a 16/125/128 one - the system cost of effectively doubling the memory size would not have made sense)
These days (and actually in those days too) memory isn't really the size of the memory bus, often it's a power of two multiple - those 9-bit RAMBUS drams we were using really moved data on both edges of a faster clock - our basic memory transfer unit was 8 clock edges x 9 == 72 bits per core clock - as a designer with even 1 DRAM out there that's the minimal amount you can deal with and you'd best design to make the most of it
My point was there was more than one way of solving the problem (economically optimized or not), and having custom width memory silicon wasn't the only answer. But sure, if you move the goalpost around enough you get to be right.
