Now that club fees are almost $3k a year, I strongly believe that club soccer will experience a decrease in participation. Also there's the fact that younger kids are not into sports as much as older generations. Just look at the TV ratings.
A correction of supply and demand will be happening as early as next year.
I am already seeing this in north Orange County. Fewer kids are trying out at the younger age groups.
Its not the $3k/yr that makes a difference. Its what percent of their income that will determine if the participation will decline or not.
If the cost of club soccer is the same or lower than what it used to be for any given family by percent of their income, the I would not expect a change of behavior - all other situations being equal. But if it is larger percent of their income, then probably would happen.
So the real question is has the average family income increased to keep up with the increase in club soccer fees.
As for decline in sports, I highly doubt it. The composition of the sports and the medium in which its viewed have clearly changed. More kids are into e-Sports and are watching on their smartphones. Some sports have seen increase in popularity: whereas, other have seen decline, but the total I believe has remained steady.