Anyway the problem I see is that other languages and tools are also improving, for example the author of this post (2) "I am reluctant to shift to Symbolics, as the calculus specifics (limits and integrals) aren't as competitive".
(1) https://discourse.julialang.org/t/discussion-on-why-i-no-lon...
(2) https://github.com/jverzani/CalculusWithJulia.jl/issues/50
Edited for grammar and spelling.
All the bugs he listed as "filed by others" also seem to have been fixed, again save for one: https://github.com/JuliaLang/julia/issues/36069.
I'm not sure I understand what you're getting at with (2).