Why is it that in our days few Minyanim pray for the peace and welfare of the land we are in, when it was customary to recite such a Tefila on Shabbat in the past?

Seforim mention different opinions regarding the Prayer for Shalom Malchus. It is mentioned by a known Mishna in Pirkei Avos (Ethics of the Fathers 3: 2) “Rabbi Chanina the assistant to the high priests would say Pray for the well-being of the government, for were it not for the fear of its authority, a man would swallow his neighbor alive” Rashi, Rabenu Bachya and others maintain that one should also pray for the rulers of Gentile governments, as is mentioned in Yermeyahu (29: 7) “And seek the peace of the city where I have exiled you and pray for it to Hashem, for in its peace you shall have peace.” Midrash Lekach Tov (Miketz) on the verse (41: 16) ‘And Yosef replied to Pharaoh, saying, “Not I; Hashem will give an answer that will bring peace to Pharaoh,” that it is the source for praying for the well-being of the government. Most Poskim maintain that this Tefila is only a tradition and not an obligation (See Machatzis Hashekel, Aruch Hashulchan 284 and others). However some differ. Michtav Sofer (O.H. 1) quotes Meiri (Avoda Zarah 4a) that it is indeed an obligation. Seder Hayom mentions that it is a mitzva ‘Midivrei Kabbala.’ Seder Yaakov (ibid.) explains that from the fact that Rebi did not set this principle in the Mishnayos of Brochos but rather in Pirkei Avos, shows that it is not an obligation but just a tradition. The Prayer for the Welfare of the State, is still a fixture in many synagogues on Shabbos morning, not just in Britain, but in shuls around the world. Throughout the centuries in the many lands of our exile, synagogues faithfully followed this rabbinic injunction. Horav Shlomo Miller’s Shlit’a opinion is that as usual every community should follow their established traditions.