@looking glass  
I’m always disappointed at “modern” fantasy settings that are essentially just stuff you’d see walking out your door but with magic on top. Actual Human History is an ongoing story of technological differences deciding the fate of great empires, and of tech advances which spread rapidly altering the direction of societies; there’s zero reason to think that something as game-changing as every person having their own magic powers wouldn’t lead to some weird divergences and odd juxtapositions. Technology exists to fill a role and satisfy a specific need, and if that need is met by, for example, a third of the populace being able to make plants grow in otherwise highly unlikely conditions, that would have a massive effect on whether such technologies as tractors and artificial fertilizers and pesticides are even explored in the first place, much less highly developed.
 
I think it would be off-putting and immersion-breaking if Equestria didn’t have schizotech.

I do know the “meta” (aka:IRL, behind the scenes) reason for the relative “lack of tech”, or at least, the lack of focus on the technology: || The showrunners wanted a “timeless” show, and if there was too much modern technology displayed, it would make the show “dated”. Also, things like horsecarts were put in there because Lauren wanted ponies “doing pony things”. (Aka, “realistic” pony behavior) she thought the ponies in the past shows were “too human-like”.  
||
 
As for the “in-universe” reason, I’m not sure. Personally, I surmise we just don’t see all the stuff they really have. Technology wise, I would put them as 20th century. As for things like horse drawn wagons, my guess, the tech evolution differed slightly than humans, and they never saw the need for cars.

@TexasUberAlles  
I know, but it’s just that video games are commonly associated with TV because without the first arcade sets in the late 1960s having TVs for their screens instead of specially-made electronic displays, we’d still be using radar equipment. As for movies, I can admittedly see a Universe where cinema exists and TV (in it’s current state) doesn’t - it’s called the 20s and 30s.

@EmployeeAMillion  
They still got to movie theatres and video games before TV. How do you even do that!?  
Do you know what a “talkie” or “pinball” are?
 
@DanielTepesKraus  
technology really does lack consistency  
I know for a fact that mine ain’t the only house in the county where a flatscreen TV is sitting on top of the CRT it replaced because the old one is more useful as a shelf than a video display now even if it does still work.
 
Also I still have a functional Windows 95 laptop.

@Danilo  
They still got to movie theatres and video games before TV. How do you even do that!?

Don’t forget DJ record players and laser light shows:  

I saw cylinder mowers at HomeDepot last week… right next electric battery mowers.

@DanielTepesKraus  
I wish I could touch your badges.

And still no TV

@DanielTepesKraus  
That’s a lot of fish badges.

@MezzoDragon  
this is true, but this artist says hi

@DanielTepesKraus  
That true. And… you have a lot of badges.

@MezzoDragon  
technology really does lack consistency. in the last 50 years we’ve gone from radios with tubes in them that require taking out a second morgage to purchase, to microcomputers that children carry around in their pockets.

Maybe this tech is 20th century

Technology: One of the numerous things that lack actual consistency in MLP.