Wudu is Wajib (obligatory act in Islam) to touch the Quran, this is the consenous of the 4 Imams…Imam Abu Hanifa, Imam Malik, Imam Hambal, and Imam Shafi….
If the 4 Imams consider it to be Wajib (obligatory act in Islam), then it means, that from the early days of Islam, this action would have been considered Wajib (obligatory act in Islam)…because these 4 Imams were very active in Masail of Islam, from the period just after the Sahaba Radi Allahu Anhu.
If the early scholors, that were alive, just after the period of the Sahaba Radi Allahu Anhu, who are we to argue with what these early scholors said or wrote…