In south east asia the argument can be seen differently - but even so, the US protects SK, Japan, Taiwan, and Australia to keep open the South China Sea. If that benefit disappeared the US wouldn't be as vigorous in its defense.
The reason presidents prior kept NATO together was because it is an extremely strong alliance that can protect each other's economic interests. If the US loses NATO now, they are simply no longer hegemon.
I think the US would be fine without NATO. The US projection would be mostly undamaged. Not so much the rest of the allies. It's the rest of the NATO that benefits from that projection (e.g. Somali pirates missions).
BTW I very much do NOT want NATO to disband. I think it's a great alliance. But let's be realistic. The US pays for alsmost 1/4 of the NATO direct spending, and 2/3 of the indirect spending:
https://www.factcheck.org/2018/07/trump-still-distorting-nat...
I understand we benefit from that too, but why should we carry the burden more than the direct beneficiaries?