We don't know what size or type of cat is in what bag. The widely-adopted
assumption is that PS5 will include a big (for many games) and fast SSD because the quote strong implied it was very fast.
Sony could just be slotting in 64Gb of fast solid state cache in front of the HDD which virtually eliminates loading once the data has been read once, but continued to use a HDD for mass storage. There is a lot of neat trickery in the way PS4 games are packaged to let you play before the whole game had installed or downloaded and maybe PS5 has an extension of this.
A silly competitor could easily prioritise a big 1Tb SSD and blow a chunk of budget on that but Microsoft really can't because they will already be pretty committed to what they have been designing for past few years. So the options are to increase the cost (or reduce the profit margins) by throwing in a conventional SSD or try to retrofit a similarly smart solution.
Or maybe Xbox 4 already has something similar! Those engineers are Redmond are pretty smart and probably hate slow-loading games as much as the engineers at Sony