negotiate to those ends in future cost-share agreements
The cost-sharing has already been negotiated and it has been ignored. What you're calling for is forgiving these nations for not living up to the treaty, exactly what Trump is pointing out. These countries know that much of the current government doesn't mind that they don't pay their fair share. People like yourself don't mind. You consider their non-payment to be worth their supposed alliance. I don't. If a country can't defend itself and instead wants us to defend them instead, we should just annex their country or abandon it entirely. Clearly they don't consider their country to be in danger, right?
none of what you're saying is very congruent with how nato funding works. the nato common fund (the one to which member states contribute directly) is small. the total us contribution to the common fund is ~$750 million, so there's virtually nothing to recoup there.
the 2% figure that your graphic cites is individual member nation defense spending as a percent of gdp. that means there's nothing to recoup. we're not gong to cut our own defense budget because albania or whatever decided to spend more. trump is categorically wrong that we "[spend] trillions of dollars over time – on planes, missiles, ships, equipment – building up our military to provide a strong defense for Europe and Asia." we spend trillions of dollars on our military to support our own national interests. we support nato because it's in our national interest. defending europeans is incidental.
By not spending the appropriate amount of funding on their military, they're opening themselves up to being attacked by outside forces, which then we have to intervene. An analogy would be you have car insurance and the insurance company says you must change your oil at least every 10,000 miles or your insurance claim might not be approved. You've chosen to change your oil every 25,000 miles instead, putting your engine and car at higher risk of damage. Assuming the company knows you did this, they'd dismiss any insurance claims you make because you neglected to handle your own risk profile.
These countries believe that since the US is backing them up, then they don't need to put forward an expected amount of their own people, equipment, or infrastructure to fight off enemies. Again, why should the US defend someone not even interested in defending themselves? If this is all about the US' best interest, then clearly we can do whatever we want without NATO since the other countries in NATO have an almost nonexistent military regardless.