You can also choose to ignore the reason-by-analogue I gave, and just take my prediction as a bet. I offer even odds at a 100 bucks that this ttl stuff will still be in the Linux kernel in 20 years.
I didn't ignore your reasoning, I acknowledged it and said it was not insightful.
Unused CPU instructions are difficult (but not impossible!) to deprecate for completely different reasons than the critical functionality of line discipline that is used all day every day and for which nobody has proposed a viable alternative.
