Rabbi Yehudah’s opinion is that the sukkah must be fixed and his opinion has already been explained (see Rambam to m. Sukkah 1:1) therefore he requires that it be able to stand on its own … and the Halakhah does not follow Rabbi Yehudah.
Rambam expresses his opinion succinctly and clearly in his Commentary to Mishnah (2:2): ר’ יהודה סובר סוכה דירת קבע בעינן, וכבר נתבארה לך שטתו, ולפיכך מצריך שתהא יכולה לעמוד בפני עצמה … ואין הלכה כר’ יהודה.