That is incorrect. If there are 4 of you and one enemy, giving up your action to cancel the enemy’s action is a great deal. The break even point is when there are 4 of you and 4 of them.
Of course, if you are in a 4-on-4 situation, your high-level heals are probably outpacing their damage.
This is only true if your opponents are exactly as capable as your allies, and (more importantly) your action does, in fact, completely negate the enemy action. Both of these things are usually incorrect in 5e.
If you face a horde of small monsters, explicitly intended by 5e rules, negating only one enemy turn is wasted effort. Defeating multiple enemies is always better--not just in an ideal case, but in practice too--than temporarily inconveniencing a single opponent. If you face a "solo" monster, it will almost always be designed to actually threaten a whole group of PCs, and thus it will be very hard to completely negate the actions the monster takes. (Unless you're a full casters using offensive spells, of course...)
Suppose you are 4 5th level adventurers. You are fighting 4 CR 2 ogres. On average, your 2nd level and 3rd level heals are handily outpacing their damage. Your heals always hit. Their attacks don’t.
Sure. Such fights also don't require much if any healing in the first place because they are way below par. Seriously, 2 CR 2 creatures against a 4 person 5th level party?? You could hardly make a less useful point of comparison. Even with the "difficulty multiplier," your example encounter is explicitly Easy! (Easy is 1000 difficulty-weighted XP, Medium is 2000, fight is worth 900 with difficulty multiplier 1.5, net difficulty is 1350, so this is a fairly Easy encounter.)
In fact, against AC 16, if the cleric has 16 Wis, your 1st level heals are keeping pace with the ogre’s hits, given that he needs at least a 10 to hit the player.
And I would expect an "Easy" encounter to work that way, imagine that!
The combats mostly rely on iterations of an attrition model, and tension in combat (to the extent it is generated in 5e) would be dissipated by increasing the amount of healing to equal the amount of damage during combat.
Okay. What about bumping healing up, but making it so characters can only be healed (by any means, including magic) "half proficiency + CON" times per encounter, but freely outside of battle? Gives merit to having a positive CON, doesn't require fancy or elaborate changes, and very much creates tension rather than removing it, while making people who derive joy from healing feel pretty great. Further, it gives players a reason to avoid "whack-a-mole" (they cannot rely on being popped back up), and a reason to consider ablative or non-healing sources of protection (THP, AC buffs/enemy hit debuffs, evasive tactics, etc.)
Frankly, it seems clear to me that you get everything you want AND let others get what they want by doing something like this. As opposed to having to add even more punishment/outright banning of valid, smart tactics ("whack-a-mole") on top of further reducing things other people like and that you don't really care much about (making healing feel chunky and worthwhile).