Why did the Rightly Guided Caliphs turn away from performing Tamattu' Hajj to Ifrad Hajj?

The rightly-guided Caliphs, may Allah be pleased with them, shifted to Ifrad (definition) (performing Hajj alone), as they believed that Tamattu' (performing 'Umrah (definition) then Hajj, with a break in between) would leave the Sacred House deserted for the rest of the year, given the arduous nature of travel at the time. Thus, they preferred Ifrad to ensure the House remained frequented throughout the year. They also interpreted the Prophet's command, peace be upon him, to perform Tamattu' as a means to abolish the pre-Islamic belief that prohibited 'Umrah during the months of Hajj. Sheikh al-Islam Ibn Taymiyyah held the view that performing 'Umrah on one journey and Hajj on another is unequivocally superior. However, there is some reservation regarding this, as Tamattu' is absolutely superior because the Messenger of Allah, peace be upon him, commanded it and encouraged it, and adhering to the general meaning of the Messenger's words, peace be upon him, is more appropriate.