I think the answer is truer than it is popular. D&D has been heavily criticized as being 'violent' (from outside the community) or 'roll playing' (from within) for so long that it's almost reflexive to regale folks with how much ROLE-play and non-combat there is in D&D.This may be an unpopular answer, but when I run D&D we have a lot of combats - probably 65-75% of our time playing is in combat.
6-8, yes.As it has been said, 5E heavily suggests 6 or 7 combat encounters per long rest,
Not so much. While 5e combats can be fast, especially the easy ones, sessions can also be short. At my FLGS, AL isn't limited to 2hrs like Encounters was, but it's still a Wed evening...and a long rest to heal from combat is expected to be done one per session.
I've noted this before, but I think "combats per session" is an inaccurate form of measurement. How do you gauge your "1 or 2 per session" versus my "4 per session" without knowing if my sessions are 12 hours long and yours are 2 hours long?
To me a better measure is "combats per hour", where the number is a positive number, whole or fractional.
In my case, in our 5e games it probably averages to about .5 per hour. In a four hour session, we typically have two encounters, one fairly small and quick, with one being more substantial.
In our Pathfinder games, we average about .3 per hour - but one session might be all roleplay, and the next a two hour grand melee in the three bour session. Or, we might have one combat in between three hours of exploration. Due to the length of the combats, it takes on a different rhythm from 5e, which are far quicker, to the extent we can have more combat than our Pathfinder games, but it doesn't feel convoluted.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.