To a degree, yes. But, at higher levels, you could also have NPCs enemies and spellcasting monsters dropping really dangerous AoE stuff on the party, so it's a wash.
No it is not awash, sure they have powerful abilities but yous spells beat those. Counter spell BEATS a spell of equal level and has a good chance of beating a spell of higher level and that is before you make the save. Death Ward Beats disintegrate beforeyou even have to roll a save.
I find 1st level to be the most deadly and this is directly counter to this hypothesis. If the hypothesis were true things would get harder as you level and they don't, they get easier. I have only had one character over level 3 hard die in a campaign in the last 3 years and he only died because he sacrificed himself to close a gate too the elemental plane of water and then drowned on the other side of it, he did not actually die in combat from failing a save.
Low level characters may have to deal with an Hold Person targeting a couple party members.
High level parties may have to deal with an enemy using Psychic Scream on the whole party, or a multitude of lower level enemies using Hold Person, Phantasmal Force, Hypnotic Pattern etc at the same time.
Hold person is going to kill 3rd level characters A LOT faster than psychich scream will kill 17th level characters.
14d6 is not going to kill anyone at that level and while the stun is significant, counterspell cast at 3rd level will flat kill it 35% of the time ON A 3RD LEVEL SLOT and chances are you are not going to counter at 3rd level, you are going to use the highest slot you have.
If you are close to the Paladin you have a +5 to your save. If it takes effect dispel magic or cleansing touch eliminates it and many characters are probably running around with a contingency if they get immobilized like that.
On top of all this your Wizard has proficiency on this save and so does his Simulacrum and both of them have counterspell, dispel magic and if you knew you were going up against an enemy with psychic scream they probably have anti-magic shell.
The point is everything I mentioned here is available LONG before psychic scream is available and before you say "only if you prepared it" ...... if I am pushed I can use wish to create any of these effects, so I only need to prepare one spell to have all of these options at my disposal.
You don't even mention non-legendary monsters (that is, 95% of monsters), so I assume you're conceding the point that the vast majority of monsters are complete trash at saves.
I was respnding to someone who made a point about legendary monsters specifically and claimed (falsely) that even legendary monsters don't have good saves other than legendary resistance. I believe I qouted him if you want to take that in context.
In play enemies make saves all the time. It is quite rare that you throw down an AOE or multi target spell and all of them fail. By contrast it is far more common that you target a single enemy and he makes that save.
I stand by my point on Legendaries, too. The examples of legendary monsters you provided say it all: a mighty Red dragon is extremely easily affected by an Int save, and you have a fair shot of nailing its Wisdom, too. Without the blunt and inelegant (but again, absolutely necessary) Legendary Resistance feature to patch things up, the red dragon would be screwed.
Not easily. For one thing he will flat make 25% of his intelligence saves against a 20th level caster, even without legendary resistance and he is a 13 CR enemy, so he should not be going against a level 20 caster. Against a level 13 caster he is going to make 35%, against a level 8 caster (which is probably when you would meet him) he is going to make 40% of them.
Why don't you tell me what spells your 8th level Cleric, Druid or Ranger are going to throw against this Dragon's intelligence that are going to completely overwhelm him and turn this into an easy fight?
As for the beholder? Putting aside how exceedingly easy it would be to target its Str s
Examples of spells you would use to target strength saves and take down this beholder please.
Nevermind how easy it is to shut down a beholder with a single darkness spell casted over the party...that's just an embarrassing design oversight that has nothing to do with saves.
Sure, but this has nothing at all to do with his saves.