It’s pretty much like that, becasue that’s the way it is around the rest of the world, some places in Europe use even frequencies, & NZ after their restack use entirely even freqencies?
Standard channel spacing is 800kHz apart or 0.8MHz.
Standard FM channels are 200kHz wide, your theory on frequency use (as example given) wouldn’t work though, as both channels would butt up to one another, (top channel frequency on one would butt against bottom frequncy of the upper channel, with no guard space). Transmissions would have to be tightly monitored, & enforced to the limit of 75kHz deviation, which very few stations currently adhere to. If you go over 75kHz deviation your channel gets wider than 200kHz & would overlap with each other causing interference, even at the distances you noted. Given this would be better than the current co-channel interference, still not ideal or desirable for the amount of works needed to be done to change the status quo.
DTV works with adjacent channels well, but that’s becasue unknown to most people, even though the allocated channel bandwidth is 7MHz, at maximum multiplex capacity, it doesn’t use the enitre 7MHz, there’s a guard band at the top & bottom of each channel, which is doubled in size, when added together from top & bottom adjacent channels, giving all carriers within the channel block a clear & interference free space to operate.
The FM band could be tightened up & use both odd & even ending frequencies, but idealy you’d still want 300kHz spacing to allow 100kHz in each top & bottom channel & a 100kHz space between them.
For example in Newcastle you could have 102.1, 102.4, 102.7, 103.0, 103.3, 103.6, 103.9, etc.