Using your analogy, you can argue that training and work experience provided by a foreign company is like building ports, roads, or other infrastructure that is necessary for trade. Infrastructure, as long as it’s used well, is undeniably good for a country.
Also, if wages were based on net revenue generated from a worker, that would 1. be impossible to measure, and 2. remove any incentive for a company to hire Filipino workers.
Another issue is that you really can’t build a country efficiently like the way you describe it. Trade is necessary to get good technology, and investment is needed to get said technology within your country’s borders. Effectively banning trade is just like shooting yourself in the foot and getting your other 3 limbs chopped off.
I understand your argument, but a living wage in the Phillipines is lower than a living wage in the US. As long as the employer is properly compensating their employees, I think it’s unfair to blame said employer for the Philippines’ economy. Even if this transaction is more beneficial to the US than the Phillipines, it would still benefit the Philippines, no? More outsourcing should mean a more trained labor force and greater purchasing power from exchanging USD for pesos.