> So basically everybody should model their language after Finnish.

Sure, as long as you assume the only goal is to validate a phonics approach to teaching reading. Some people appreciate that english words get the same spelling in Minnesota as they do in Mississippi.

English pronunciation <-> writing is so far from a mapping, it causes a lot of resource waste.

For foreigners like me that mostly use it in text, the biggest overhead is in speaking, for example I always mess up the words study and student, it's infuriating.

Even if there are dialects that pronounce the same word differently, you could still find a lot of common ground.

Finding that common ground would mean switching from our current system of somewhat-arbitrary spelling to a different but very similar system of mostly-arbitrary spelling. It imposes the same memorization burden on everyone and the benefit is slightly more predictable pronunciation within each of a set of officially-blessed dialects. That ground gets lost over time regardless; there is a reason predictable pronunciation is a feature of spelling systems that either (1) are new, or (2) have just undergone reform.

If your biggest problem lies in a circumstance you rarely encounter, arguably fixing it is not a priority.

> for example I always mess up the words study and student, it's infuriating

This is a funny example to use, since it fully conforms to the rules I described above -- study uses the STRUT vowel, and student uses the GOOSE vowel. It would be a better example for the complaint that we have more sounds than symbols.

Good points, but I disagree. Decoding and encoding becomes a lot harder, if vowels change depending on consonants coming after them, or something else even further down the line. (I'm not a linguist.)

It's like a config file specification that supports gotos.

So there are no dialects in Finnish? I remember my Norwegian teacher telling me the same ludicrous thing 30 years ago when I moved to Norway.

There are, like in most other places. What's usually written is the so called "general language". You can also speak that in a formal setting.

It's like in English, if you say "y'all" and write "ladies and gentlemen", you understand that those might mean roughly the same thing but are different words. It's not a spelling issue.

This is an important but hard to articulate distinction. Ask more if it's unclear...