Tourist, the US military have an enormous size advantage and both their naval and marine air arms leave the RAF in the shade. As for the one-to-one qualities, I have served in the USAF and there is no shortage of either skill or professionalism. However, a big air force will inevitably carry a lot of low average abilities as well as a lot of high average abilities but quantity has a quality all of its' own. They also have better equipment.
Could they benefit from one air force serving all three services - they thought so when they formed the USAF but they could probably place more assets in the air force and less in the marines and navy. Nevertheless, each of the latter two air arms are large enough to generate a core professional force capable of fully understanding the air part of their profession and producing the number of senior officers to manage the air assets professionally.
It is not size and money that produces bang for buck it is recruiting, training, skill, experience, equipment and utilisation of assets to name but a few of the attributes of the RAF.