Treantmonklvl20
Explorer
When you DC is 18, and you're fighting a high level NPC with a Wisdom save of +0, then hold Person is the "I win button" in the game. Even creatures with really high Wisdom Saves still have around 50/50 chance of being stunlocked by this spell when your DC starts getting high.
At low levels it's not that great, at high levels it's freaking amazing. You can take out CR20 NPC's with a 2nd level spell.
Forcecage is actually similar, and you've rated that as a poor spell. It's kind of broken. The only thing that makes it not broken is the fact you can only cast it once per day, but it's your "I win" against anything huge size or smaller, including many Dragons. Getting the material components is easy. My group got them after killing a enemy caster with those components, but once you get high levels 1500gp worth of rubies is easy to come by.
Are you playing high level games?
I changed my Forcecage rating yesterday. It is currently blue. My original rating was based on the mistaken assumption the material cost was per casting.
As for hold person, yes, with a failed save, an applicable target is super-screwed for a round. With each additional failed save, screwed for another round. As I mentioned in the statement you quoted, lots of spells screw the target who fails a save, though many don't provide saves every round, or affect multiple creatures, or have a wider variety of applicable targets, or don't require concentration.
Hold person can win a battle. Otto's irresistible dance can win a battle. Slow can win a battle. I just don't consider these the best options compared to the competition.