Was the number of prayers 40 in early Islam, then reduced to 5 as a mercy from Allah to His servants?

The correct view is that Allah Almighty ordained fifty prayers a day and night during the night of Al-Mi'raj (the Ascension). Then the Prophet, peace and blessings be upon him, had them reduced to five prayers, yet their reward remains that of fifty prayers. Al-Bukhari and Muslim narrated from Anas ibn Malik that Abu Dharr reported that the Messenger of Allah, peace and blessings be upon him, said in the Hadith of Al-Mi'raj: "So Allah, the Mighty and Exalted, enjoined upon my Ummah fifty prayers. I returned with that until I passed by Musa, who said, 'What has Allah enjoined upon your Ummah?' I said, 'He has enjoined fifty prayers.' He said, 'Go back to your Lord, for your Ummah will not be able to bear that.' So I went back and He reduced half of them. I returned to Musa and said, 'He reduced half of them.' He said, 'Go back to your Lord, for your Ummah will not be able to bear that.' So I went back and He reduced half of them. I returned to him and he said, 'Go back to your Lord, for your Ummah will not be able to bear that.' So I went back to Him, and He said, 'They are five, and they are fifty; My word does not change.' I returned to Musa and he said, 'Go back to your Lord.' I said, 'I felt ashamed before my Lord.'" Al-Hafiz Ibn Hajar said: The meaning is: they are five in number in terms of action, and fifty in estimation in terms of reward.