Exactly. Just don't mention how D&D is pay to win just like some video games. The terrible classes are free. The PHB comes with better classes and is $50. The "new" artificer class is in Tasha's which will cost $50. And the beast-mode warlock is in Xanathar's...which will cost you $50.
I mean, that's just not true.
The best Warlock Patron is The Fiend. That's in the PHB.
The Hexblade (Xanathar's, presumably what you're referring to) is about equal, maybe a little inferior, and Pact of the Genie in Tasha's is about equal. All the rest are somewhat weaker, but only The Fathomless and The Celestial are even close to bad (also Xanathars and Tasha's)
The best Pact is Pact of the Tome, which is in the PHB. There are no Warlock pacts in Xanathar's. And even with The Hexblade patron, that only fixed Pact of the Blade, rather than making it better than Pact of the Tome.
The Artificer class is one of the more mediocre 5E classes. No-one who is seeking power is playing an Artificer unless it's for some obscure Magic Item Replication-based exploit.
It's true that the Basic set subclasses are kind of mediocre, but not all of them - let's look:
Barbarian - Berserker - I'd say this is a weak one, some people violently disagree. If your DM houserules Exhaustion or fails to track it, it's amazing.
Bard - Lore - Straight up the most powerful subclass in the game to this day.
Cleric - Life - Extremely good domain, period.
Druid - Land - Deeply mediocre.
Fighter - Champion - Mediocre but surprisingly effective.
Monk - Open Hand - Not the best but nowhere near the worst.
Paladin - Devotion - Equal-best subclass for a Paladin.
Ranger - Hunter - Mediocre, but literally all the PHB ones are too because WotC are inept.
Rogue - Thief - Decent, not the best.
Sorcerer - Draconic - Solid at worst, some people regard it highly.
Warlock - Pact of the Tome is there, and The Fiend is the Patron - So this is best Warlock and you're wrong re: "beast-mode Warlock" requiring Xanathar's.
Wizard - Evocation - Decent, but yeah it's not Blademaster or Divination.
So I'd have to say your assertions are largely false here. We've got a mix of top-tier and mediocre subclasses. Only Druid and Ranger even arguably have "bad" subclasses.