Maxperson
Morkus from Orkus
Incorrect. Mine do those things and sometimes are able to see things coming. Besides, by the time you are relying on perception proficiency to let you know the enemy is nearby, you don't have a minute to cast a spell.You are using a data sample of players who don't bother doing basic things like scouting, using divination spells, taking Perception proficiency, to see what enemies might lie ahead.
And divination spells are few in 5e. Slots are at a premium and you are wrecking your combat ability if you are using a lot of slots to scout around for 16-24 hours looking for those 6-8 encounters. You don't get to have it both ways. You can't be gods outside of combat and inside of combat both. That's not possible in 5e. You need to pick a lane or else be mediocre at both.