I'm a fan of F1, but tell me again why we don't have a legit American racing in that series? What happened to Logan Sergeant?
Solid questions. First problem: Logan Sargeant was pulled up from the minors too early. He may have never performed at the F1 level, but the way James Vowles handled that situation doomed LS to failure. That said, Logan was given 1 1/2 seasons to show his worth and didn't improve, so I also question if Vowles just misjudged the talent.
To the main point, and I'll take it at face value and not rhetorical, so apologies if I'm out of line. This is also a lengthy explanation because of the process. BLUF: Americans in F1 are limited by their lack of international karting and racing.
Up until the 90's/ early 00's a driver from another series could make it to F1. While most would go through the feeder series (the names have changed massively over the years), you still had guys crossing over from endurance or whatever. Now? You have to be an excellent international kart driver to stand a chance. These kids are managed starting around 7-8-9 years old. Europe has a number of karting series and the kids race in all of them, hoping to step into a base model open wheel car at some point.
Max Verstappen: Starting at 8 years old, karting for 8 years.
Max Verstappen - Wikipedia
Lando Norris: 7 years old, karting for 8 years.
Lando Norris - Wikipedia
Lewis Hamilton: 8 years old, karting for 8 years.
Lewis Hamilton - Wikipedia
Charles LeClerc: 8 years old, karting for 8 years.
Charles Leclerc - Wikipedia
Once they step up to a car, their next hurdle is to perform well enough that they are signed to a junior/ driver development program. Some bounce around from say...McLaren to Ferrari or whatever while others remain with one program until "the end." The F1 teams are locking in their drivers and rewarding performance Survivor style for them to move up through the ranks. As they are closer and closer to F1, it becomes apparent who will be cut, who will go to say an endurance team, leave for Indycar, whatever.
But there's another problem: money. None of that is cheap and drivers (their parents) fund them until they can land sponsorships. Parents are going broke, already starting with a pile of money, taking multiple jobs, etc. to fund their child's dreams with no guarantees of a future.
Back to Americans, if they want to move into F1 they have to follow the path above, that's what Logan's family did. They moved to the UK for his career when he was a kid.
His dad is a billionaire. An American would have to move to Europe and/ or perform well in American karting (and probably still move to Europe) to stand a chance at F1. Indycar isn't as structured, but also the money isn't there. Another factor is some Indycar drivers were low to middling F1 drivers.
NTT INDYCAR SERIES Drivers | Official Site of INDYCAR
Unless I miscounted, 17 of 34 are Americans. US-based series and 50% the drivers are Americans. (Of course, one's an Andretti and another's a Rahal, with a third the stepson of Tony George and owner of his own team so we could probably subtract them. Kyle Larson went from dirt open wheel to NASCAR before Indy. We could probably write off these 4 to be honest because they aren't the norm.)
The top 5 Americans have similar, though not as rigid, backgrounds. US karting, some international karting and open wheel, before returning to the US to race in US-based Indycar feeder series like Skip Barber and Formula Ford.
So, the F1 guys remain in Europe, performing at high levels of international racing. Indycar drivers tend to spend most of the time in the US before going to Indy and rarely receive international exposure.
There's a long-winded answer and I'm not proofing for gooder English. Kudos to anyone who made it this far.