All I can say is that doesn't match my experience. Single rounds of play could take an hour or more.I guess my main question here is where you using MMI monsters or monsters from later books?
I actually wrote a guide back in the day which was a guide to anti-grind (one of my most popular posts other than my Obsidian Skill challenge system): Stalker0's Guide to Anti-Grind
However, I found that later monster designs had fixed some of the grind issues I had complained about, and they ran very quick. The thing is 4e characters just don't have the innumerable bonuses and statuses and XYZ of 3.5 to worry about, they aren't having to literally rewrite their character sheets after getting hit with a dispel magic, etc.
So I just never found 4e combats that grindy and slow, again I think they ran longer than 3e and 5e combats but that was due to number of rounds, not time per round. So the combats were "longer" but felt "quicker"

In any case, water under the bridge since I don't play and don't plan on ever returning to 4E.