It takes a while to develop your filmmaking skills - and a lot of those skills have absolutely nothing to do with the camera you've got. So why spend a lot of money up front for equipment that you may not be able to get the most out of for a few years? By the time your skills have caught up with the capabilities of your equipment it's likely been superseded by whatever the latest technology is.
Plus, the cameras at the mid- to high-end tend to all have their own quirks, strengths & weaknesses, and sometimes vastly different workflows. If you don't know what you're doing when you pick one you're just as likely to find yourself wanting to buy a different camera in a couple years once you've figured out what kind of workflow you prefer.
If you're going to learn to light well, it's going to take just as much work to light for a cheap camera as an expensive one. You might have to adjust your ratios a little differently, but that's about it. It's going to take exactly the same amount of work to get the best performance out of your actors. It's also going to take the exact same amount of work to record the best location sound. The time you put into your script and storyboards is going to be exactly the same. You're likely to have to put in more work on your production design with a 4k camera compared to an SD one, and you'll definitely need a better make-up artist. The bigger your camera, the more expensive and complex your support equipment needs to be. If you're shooting raw the post workflow is going to be more complicated and require significantly more storage (both in camera media and hard drives) and more powerful (and expensive) hardware. Shooting raw or log will require you to be a lot better at color correction as well - or find someone else who is.
Cost aside - why burden yourself with all of that if you're still just learning the basics of filmmaking?
The problem is you could go out and buy an alexa tomorrow and it wouldn't put you on any more of an "even playing field with other filmmakers" if you don't have any experience yet. Hell, even if you have a lot of experience it might not - there are too many factors involved in making a good film for the camera you've got to make that much difference. I've known several filmmakers over the years who made features with expensive cameras that they weren't really skilled enough to understand, and made simple mistakes in camera settings which caused them problems with distribution later.
There's a difference between learning and practicing a profession. When you learn to play basketball as a child you're probably not strong enough to get the ball even close to a regulation hoop, so you start with one of these:
If you can't even make a shot on that, you're not going to get any better practicing in madison square garden - not even if you buy the same shoes the pros use.
Though that was at the age of ~12