I'd just disable them. Speed and lighterweight (on CPU) rendering are more important that ligatures and transparency, which are both gimmicky features.
That said there may? be languages other than English where ligatures are more than decorative, and would be more useful to have in a terminal.
They could start by not mimicking 50+ year old hardware terminals down to arcane (and performance killing) details, supporting better and more powerful autocomplete and similar interactions, inline images, full colors, and so on...
Not about setting ligatures for print.
So the whole argument is kind of moot. Having ligatures in console vi is not what made the Mac "historically be far ahead of other platform". In fact for the first 15 years of its life the Mac didn't even have a console.
Even in the desktop GUI program world, where ligatures in programming IDEs and editors are a possibility, they're still an extremely fringe endeavor.
And I might be wrong, but in that world, ligatures and transparent terminals are not really as important as rendering speed, latency, and/or less CPU load for a terminal emulator.
In fact, even where available, ligatures are a fringe option, adopted by very few people.
(I'm always talking about programming editors. Though even in print, their main domain, they're hardly mainstream these days).
Why is the thing I don't notice objectively more important than my convenience and happiness?