Hello,
I don't doubt that your arguments are valid, but they don't explain everything alone.
I say so because in the french part, that's the same, and we don't have any translation problem.
That's also more or less the same in italian and spanish parts, and since the translations have been made by native speakers, I'm sure they aren't bad.
The problem is general, that's a fact: players don't read rules. They want to play immediately and the game must be fun from the first minute on.
When you buy a new machine, do you read the manual? probably not; you are excited to try it as soon as possible, at which point it's whether intuitive to use and then you say that's cool, or not very intuitive and then you say it's shit.
For games that's often the same unfortunately. On one side, it's quite easy to understans how a dice game works after a couple of rounds even without reading the rules, and so it's quickly fun; same for a few simple card games like ninety nine.
On another side, monopoly, Uno, dominos and 1000 miles are extremely popular; many people already know how to play them before coming on the playroom; so anyway have no rules to read or perhaps just for a few reminders.
Remains all the rest: games that aren't especially popular world-wide, and/or aren't that easy to enjoy without making some intellectual effort at the beginning. Sadly, these games have quite a restricted public. By chance that restricted public makes a small solid and faithful core, and so these games won't disappear.
For the particular question of bad rule translation, I'm sorry, my english is terrible, I know.
In fact I should perhaps consider making an english translation team, as it is for other languages. In the meantime before such a team exist, if you have ideas on how I could improve the translations (and why not my english by the way), please tell me.
To be a translator, you must be a native speaker, and it would probably be slightly better if you have some french notions. The question native from where, whether american or british, is open... I have no idea what would be the best for the entire community at once.
Also with a small risk: if the english is revised by a native, it will become higher; very good for natives, but perhaps much less good for the majority of non-native. Opinions on this?