That willingness is predicated on being at war with much weaker powers / enduring FAR lower casualty rates than Vietnam / Korea / world wars.

The entire 25+ year GWOT era has resulted in 7k American military personnel dying.

Vietnam that number was closer to 60K in 8 years, when US population was also 33% lower.

Dramatically different impact on society.

Sending marines to take an island in Hormuz or a carrier under fire in the South China Sea might look a lot closer to Vietnam than GWOT in a hurry.