True -- though the modifier keys will gives access to plenty more, and we already need to use modifier keys to create common programming tokens.
7-bit ascii is roughly 127 characters (minus a bunch of control characters). If you have ~100 keys * modifier key permutations minus some keys you can't use for generating characters you'll have space for a few more characters. I'm certain it would be possible to squeeze in two extra characters there.
As I wrote:
Then, in a few generations, maybe humanity will invent a programming-centric keymap that will allow common languages to avoid some of the more prominent ambiguities that increase the complexity of parsers.
Slight tangent, but which illustrates where I'm coming from: The Swedish keyboard layout is downright idiotic when it comes to command line use and programming. It gets even worse on a Mac; where someone thought
\ are basically the same thing, so "let's place them all on the same physical key!" (modifier keys aren't evil per se, but you want the more common ones not to be behind modifier key combinations). What this leads to is that some of Swedish developers/administrators discover that it's better to learn and use the US international keyboard for regular work. (Also opens up the possibility to use a computer without problems before the custom keymaps have been loaded..).
At least to me, switching keyboard layouts to a much superior one opened up my mind to the idea that how I had been doing things might not be the best way. In fact, there may be better ways that just never crossed my mind, even with the new and better layout I was now using. Several of my programmer/administrator friends here in Sweden moved on from US International keyboard layout to custom keymaps to remove some annoyances.
My suggestion is merely that perhaps we've outgrown being limited to 7-bit ascii language tokens. And perhaps, just as some of us Swedes realized that there are better keymaps for specific tasks, developers in general might start to think that there are upsides to not being ultra-conservative about keymaps. And language developers might start to think about how Unicode can be used to avoid taking languages in directions they wouldn't need to if they just pulled in one or two extended characters.
I will note that even before I wrote the original post, I was 100% aware that none of these things will happen in my lifetime -- but one of my employees noted that perhaps the younger generations will change the way people think about keymaps when they grow up, because they are much more used to touch screens and their dynamic keyboards. Time will tell, I guess.