Wouldn’t bother me much, but it won’t pass muster.
You only do a break up if there are no competitors. Amazon has significant competitors in every business they are in. Wal Mart competes effectively for online shopping, Microsoft and IBM compete effectively for cloud services.
Facebook is actually declining right now and is losing out to Snapchat and Instagram.
Google you could make a stronger case for in certain market segments, though defining those segments could be a problem. What they really control is information.
Facebook owns Instagram.