Mate, what are you talking about?
1. Why England and Wales getting through to the next round make a jot of difference to the Premier League? It's not a League that is English, in fact almost 70% of the Prem players are not from the UK. And without being disrespectful to the Welsh league, there's not going to be a ton of players flying to Cardiff to start playing in Wales if they happen to make it out of the Group stage of the WC. And even if they did, they'd find out that the top teams in Wales play in the English League.
2. If you think Wales would help England succeed in an international tournament, then you have no clue in the history between England and Wales in sporting competition, or indeed, in History. If Wales stopped us getting out of the group they would declare a national holiday (I'm being slightly facetious here)
3. The various PL owners are not English, and our national team's success or failure has zero bearing on the status of the Premier League. That boils down to the quality of players we attract mainly because of the inflated wages, as possibly the most popular football league in the world and TV money, and the fact that in any given year, 6 of 20 teams in the Premier League have a realistic chance of participation in the Champions League, which further inflates our financial clout, and also spreads the talent out through the league. Further to the point, the Welsh FA have nothing to do with the Premier League, operate in a different country and therefore I'm struggling to understand what leverage the Premier Leagues owners have over them (and history has shown they can hardly agree with each other on easy stuff, let alone rigging a game in the world cup in a week) and the English FA's relations with the Premier League (which is not an FA competition) are not exactly simpatico.
On the US's chances, the first rule of tournament football is not to lose your first game. So yes, you are still in it. Although Iran looked poor on Monday, we also made them look poor. As you did in the first half against Wales, until they changed it in the second half and put on a player who can receive under marking, rather than sticking to the game plan that Dan James could outrun Zimmerman, and just hoofed it up there. The biggest risk for the US is that your coach didn't adapt to the change in the game and that should be a worry.