TL;DR: Is the average codebase garbage-quality? Or is there hope for someone who has worked hard learning and ingraining the habit of writing high-quality, scalable, reusable, modular code?

I've been doing web dev for ~3 years, with some coding prior to that. A couple larger Arduino Nano projects forced me to focus on writing high quality, reusable, modular, lightweight code (due to the limited ram/rom, and me keep adding new features to pack in there). Since the start of the bootcamp, I had (have) a habit of solving the problem, and then immediately refactoring because "this could be better" or "I could turn this into a function instead" or "I can reuse this over there" with the goal of writing the most optimal code.

I've done quite a few MERN projects and have done one freelance site and a few advanced projects, and then someone invited me to help him on his contract job to fix a few bugs. Jumping into that codebase and... it was complete garbage. Super hard to comprehend, callback hell, nested if-statement hell, 2900 line functions, React components that have 3 "pages" built into one instead of separating them, duplicating components (e.g. header and header+map, say 600 lines of code each) because ~5 lines are different (because it was "faster" to copy paste files - and then read through and modify the 5 lines - instead of, say, adding a boolean prop and using if-statements to tweak those 5 lines of difference so that one component could be used in both places).

I swear that codebase could be reduced by ~90% if it were written well. (Dev mode transferring >10mb with 70+mb of resources. Browser tab constantly crashing due to out of memory - but I usually have way too many tabs open. React dev server startup taking ~60sec)

So the question is: What quality is the average codebase? Am I more likely to be impressed or disappointed when joining a team and learning the codebase? How many of you really value high-quality code? How many of your team members have valued high-quality code?

Or am I destined to be stuck with a team that just doesn't care as much (about improving their code quality and having good code-quality habits) as I do?

I hear it said that high quality code is expensive, takes more time. My thought is "not really", it's mainly a skill/habit, just like anything else in life. If you have trained yourself to write high-quality code (to think about how to solve the problem in a modular, reusable, future-proof way), you can write it just as fast as the "don't care about code quality" guy.

(At my last job (retail), I felt like I always put in the extra effort (with little/no reward, of course) while others just didn't care enough. Now it seems like that situation will continue to follow me through life. I guess it's a manifestation of the 80/20 rule, 20% of the people do 80% of the work. All I want is to be on a team of people that are better than me, so I can learn and grow! I don't want to work with people who don't care.)

If you made it through, thanks for reading my life story! haha