Trump never threatened to dissolve NATO, he threatened to quit it if the Europeans didn't live up the their treaty obligations. The Europeans have been riding on America's coattails for their defense ever since WWII.
Why pretend that the US leaving NATO wouldn't be a complete disaster to the alliance?
No NATO member was "obligated" to get to 2% of GDP by a binding treaty agreement. Threatening to leave doesn't strengthen NATO, it weakens it when the core member of the alliance is constantly threatening to leave or not fight if Russia attacks, and then cozes up to Putin at the same time.
Many countries in NATO have GDPs similar to our smallest states. It is what it is, if you want the strongest ,military alliance in history. It's a small price to pay for global peace.