Christians had forsaken prayers. In fact, they did not follow Shariah as St. Paul had suspended Shariah for non-Israelit converts.
Jews did say prayers but only three times a day. They made five times into three. Ghamidi saheb writes:
Here it should be noted that the prayer was always offered five times a day. According to a narrative, [9] Gabriel himself informed the Prophet (sws) of this fact. No doubt, the Jews now offer the prayer thrice a day and one of the above quoted excerpts also refer to three prayers. However, Louis Ginsberg while presenting his research on the Talmud of Jerusalem has explained that this phenomenon is similar in nature to what the Shiites have in them: by combining zuhr with ‘asr and maghrib with ‘isha on the principle of jam‘ bayna al-salatayn (combining two prayers) they have practically made these four into two and if we add fajr to them, the total number of prayers will come out to be three. Ginsberg has pointed to the fact that in the time of the writing down of Talmud, the Jews used to pray five times a day: thrice for the prayer which is offered till now, and twice for reciting the Shema. However, later because of certain practical difficulties the prayers of the morning and evening were combined and ultimately three prayers remained. (Abraham I Katsh, Judaism in Islam, 1st ed. (New York: Bloch Publishing Company, 1954), 10.)