How rich are they expected to be? I've noticed that wages seem to have gone up from 3.5, with unskilled labor going from 1sp/day to 2sp/day, and skilled labor going from 3sp/day to 1gp/day. If you wanted to retire (for 50 years) comfortably (2gp/day), you'd need 36,535 gp, which I think is a lot more than a low level adventurer would have.

A lv1 character starts with 100/150 GP (IIRC, depending on which class you choose), which is enough to sustain the character for 3+ months with average expenses. That being said, most expenses can be bypassed with magic (Goodberry, Tiny Hut, Create Food and Water), which means that the money can actually sustain the party a lot longer than that, and that's on top of survival rules (tracking rations, travel hours, etc...) being almost completely nonexistent in 5e. As soon as the character hits lv3-5, they will probably have no compelling reason to go on an adventure anymore, except for the one made up by the player when writing their backstory.

I've heard that so long as the small army has a way to deal damage at all, they'll dominate even high level enemies. Did they change that? I think the whole idea of adventurers makes a lot more sense if they can't just send a small army to easily deal with a dragon or whatever else they're worried about.

This was a bit exaggerated on my end: yes, action economy is king in 5e, and still is in 2024. What I meant is: a 2024 Barb can have up to 17 HP at 1st level (12 baseline + 3 from CON modifier + 2 from Tough), which are worth twice as much thanks to Rage granting them resistance to all damage. Wizards will take Spell Initiate and gain a free cast of Shield. Generally speaking, characters have a higher damage output and more resources compared to their 2014 counterpart, which was already high compared to previous editions of DnD. And that's not taking into account how difficult it is to die in 5e because of the death saving throws rule.

These are not necessarily bad things: people will probably enjoy the higher floor for baseline power, and there's nothing wrong with that. There's also nothing wrong with forgoing the dungeon crawling origins of DnD in favour of more of a more theatrical/role-playing experience, which has already been pretty much the only way people has played the game for the past few years.
It's just not something I particularly enjoy or crave for. After a while, playing an overpowered character with near-endless resources in a game that seems designed around the idea of you doing cool shit all the time, it gets old. I prefer grittier experiences, which 5e and especially 2024 are unable to provide.