> The Turing test was never meant to measure intelligence, let alone define it.

Original proposal:

"I propose to consider the question, "Can machines think?" This should begin with definitions of the meaning of the terms "machine" and "think." The definitions might be framed so as to reflect so far as possible the normal use of the words, but this attitude is dangerous [...] Instead of attempting such a definition I shall replace the question by another, which is closely related to it and is expressed in relatively unambiguous words."

Clearly Turing is saying "we cannot precisely define what thinking means, so let's instead check if we can tell apart a human and a machine when they communicate freely through a terminal". It's not about fooling humans (what would be the point of it?) but about replacing the ambiguous question "can they think" with an operative definition that can be tested unambiguously. What Turing is saying is that a machine that passes the test is "as good as if it were thinking".

> Machines have arguably been able to do this for decades.

Absolutely not and it's surprisingly uninformed to claim so.