ARM vs x86

What software absolutely needs the x86 performance from the user and programmer  perspective? Why can't we switch to ARM even if it was ~4 times slower but much cheaper?

>>35
You seem to be talking about Common Lisp (and CLOS), whose purpose was to unify the most popular Lisps at time, and did it fairly well^*.
Saying that all Lisps are the same is like saying that C is the same as C++ is the same as ObjC is the same as D. They share common traits and syntax, but they're completely different languages.
The various quotes are not that difficult to understand. ' marks literal data, ` is just like ', but parts of it can be evaluated with unquotes: ,expr simply evaluates expr at runtime, and its result is added to the list, ,@ is just like ,, but the result must be a list whose elements are spliced inside the quasiquoted list. #' denotes a procedure used in a ``simple value'' context in CL.

* Hell, it may be a frankenstein monster, but there were so many Lisps out there at that time that it's a miracle that it didn't become like C++, which just tried to extend C with class-based OOP.