Agreed with everything you said. Japanese pronunciation is easy to hit in the right ballpark because Japanese uses a near-subset of sounds found in English and other common languages. But refining your Japanese pronunciation takes effort and is not something to shrug off. Anyway, here are some examples where I think English-speaking Japanese learners butcher their pronunciation:

* し is [ɕi] (tongue fronter), not [ʃi] (tongue rearer).

* ふ is [ɸɯ] (mouth more open), not [fɯ] (teeth touching lips).

* お is [o] (monophthong), not [ou] (diphthong).

* え is [ɛ], not [eɪ]. (e.g. さけ)

* つ is [tsɯ], not [sɯ]. (e.g. つなみ)

* Anything with the Japanese r. The alveolar flap does exist in American English, though it's not consciously recognized as a distinct sound. Japanese sounds funny but still intelligible when the native [ɾ] is replaced with [ɹ] (English R) or [ʁ] (French R).

* Anything with small y (e.g. kya, nyo, myu) should have a quick [ʲ] sound, not a long [i] sound. e.g. きょうと is [kʲoːto], not [kiouto].

* Vowels are never reduced; きもの is [kimono], not [kəmounou].

* But the appropriate times to suppress vowels entirely. e.g. です, ～ます, して.

* The concept of doubled consonants, not grasping it.

* The concept of long vowels, not grasping it.

* Stress is often on the first syllable, not the second.

* Intonation is flatter than in English.

* How to use high/low/rising/falling tones correctly on particles.

* A natural and even pacing of syllables, not the choppy speech that foreigners seem to exhibit.

And as an American, none of these were an issue. None.

They understand me just fine, and the details don't matter as long as they can understand you.

It seems like you saying that having an accent in a foreign language equates to not being able to speak it properly.

Edit: Getting down votes for saying this, so I will clarify.

If you reversed your arguments, claiming that the Japanese can't pronounce English sounds, you would come across as borderline racist.

So I feel like arguing about the minutiae of sound detracts from whether or not the language as a whole is harder/easier to understand.

Here's an example of close-to-native pronunciation: https://m.youtube.com/user/Dogen

He gives valuable pronunciation lessons on Patreon.

Dogen is fantastic. I’ve never met anyone on his level in real life and I’m using his lessons to improve, myself :)

I think you need to do this blind folded. If you see someone is a foreigner you'll believe you're hearing an accent. If you had to do it without seeing them I think you'd find there are plenty of foreigners that have native level accents.

I've gotten in taxis more than once at night, gave the guy directions, had a conversation, and then when he finally stopped and turned around to get the fare nearly jumped out of his seat because he was startled he had been talking to a foreigner the whole time. That's happened at least 3 times.

I'm not trying to brag, it's just my experience. I know others that can do the same.