Q:

Each generation in which the Temple wasn't rebuilt it's as if it was destroyed anew

I've often heard the phrase "In each generation in which the Temple isn't rebuilt, it's as if it was destroyed anew". כל דור שלא נבנה בית המקדש בימיו, כאילו נחרב בימיו.
I'm trying to find the earliest source for this phrase. A search on Sefaria brought six late, mostly chassidish sources:

Shemiras HaLashon (Chofetz Chaim, quoting Chazal)
Pri HaAretz [1] and [2] (Rabbi Menachem Mendel of Vitebsk, quoting Razal)
Pele Yoetz (Rabbi Eliezer Papo)
Yismash Moshe (Rabbi Moshe Teitelbaum of Satmar)
Likkutei Halachos (Rabbi Nosson of Breslov)

I found in the Yerushalmi Yoma 1:1 the phrase: 

כל דור שאינו נבנה בימיו מעלין עליו כאילו הוא החריבו
Any generation in which [the Temple] was not rebuilt in their days, They consider it upon them as if they destroyed it

This version is much harsher, blaming the generation itself. I'm looking specifically for the earliest source of the softer version quoted above, that it was as if it was destroyed.

A:

After a quick search on Bar Ilan, the earliest source I found it in was Sefer Derech Etz Chaim, which is supposedly written by Ramchal.  It also appears in other works from the 1700s, such as this book and Chida's Moreh Baetzba (I'm assuming it was written in the 1700s).
Edit: It is also visible here (start of Chapter 50), in a Sefer published in 1731.
Most of the dozens of authorities who quoted it sourced their claim to the Yerushalmi in Yoma that you mentioned in the question, and it is possible that they had another version, or that this was just a softening of the language there.
Interestingly, in another early source, Sefer Haflaah (Kesubos 8b) by Rabbi Pinchas Horowitz , it is quoted from Midrash Shochar Tov (Midrash Tehillim) to Perek 137, however, the version that I looked in did not have it either.  (The same is alleged here).
Edit: Thanks to @Meir for the link to the quote in Shochar Tov.

