For ~40 years, since Psionics were introduced in the 1st edition DMG, until now, Psionics were treated as something other than magic, a separate power source under a separate name.
In every D&D setting that has used psionics, it's been treated as something other than spells, a distinctly "third" alternative to arcane and divine magic. Right offhand I know it was treated that was in Forgotten Realms (right offhand I remember the difference being explicitly described and discussed in Volo's Guide to All Things Magical as not being magic and being something else) and in Dark Sun (entire books written on the subject, like The Will and the Way).
At best you had the treatment from 3rd edition and later where Psionic powers and Magic spells could directly detect, protect from, or dispel each other, but even then the actual abilities were still considered distinct.
That's a vast and overwhelming consensus of 4 editions of D&D, and the "fluff" or lore of multiple settings. . .vs. a preview of the 5th edition psionic rules released a few days ago.
The fact that WotC decided to make 5th edition Psionics totally different than everything before and just make it apparently a different spell list and that's it does NOT change a decades-long consensus of D&D editions and campaign settings. . .it means that 5th edition is the one that is out of line, not that other editions and settings are out of line because they contradict 5e.