The cultural growth of a sport can take a LONG time and progress is not always linear and easy to see. Issues with the US youth sports systems aside, there is real tangible growth in popularity for soccer in the US.
I think continued growth of the domestic pro leagues is the key to everything. MLS popularity is blowing up (attendance viewership), salary growth in MLS makes it comparable to second tier European leagues (English League One, 2. Bundesliga, La Liga 2, etc.) and keeps young talent in MLS until they can make the move to top flight clubs, MLS franchise valuations where the top teams are becoming as valuable as some of the bottom end of NHL/MLB, growth of MLS youth system (MLS Next Tier 2 --> MLS Next --> MLS Next Pro --> MLS) to provide a real development pathway from U13 to pro-level. USL system as a real viable league that is expanding and going to promotion/relegation model in 2028, that can put pressure on MLS to keep getting their **** together and hopefully considering pro/rel model as well.
The sport is also just booming in popularity among youth too. Kids are every bit as obsessed with Messi/Ronaldo/Mbappe as they are with major NBA/NFL stars. Hell in my town just outside of Madison, WI soccer is THE sport. Kids hardly care about football or basketball, but they are competing for state titles (and winning quite a few) year in and year out for both boys and girls soccer.
Also don't discount the influence of massive latino population growth in the states. That cultural love of soccer isn't lost at the border and will be a big part of the growth of the sport.