I ain't no expert scientist or nothing, so bear with me here. But have you considered how mako energy actually works? There's not an explanation about the process, and examining the reactors doesn't lend much a hint either. However, from their appearance and name, I am reminded of both nuclear and geothermal energy plants.
So
What if
we were wrong and Shinra is actually the good guys with renewable energies? What if FF7 is not an example of the cruel money hungry corporation sacrificing the environment for its own benefit, but rather a parody where the ecoterrorists are resisting more sustainable methods of energy production. I mean after all Barret is a coal miner, and we all know how bad fossil fuels are for the environment.
Maybe we were wrong. I mean obviously Shinra are jackasses but maybe they've got good hearts.
I mean think about it. If the lifestream creates life and then life returns to it once dead, there's a cycle. How does changing that cycle mean that it doesn't actually complete? There's no explanation of how mako energy is used, so we could very well have a renewable energy source that everybody just mistook for something evil. Surely, once converted into energy, the mako would simply return to the planet anyway. Perhaps the biggest problem is that we don't have enough reactors and so the strain on individual areas is too high. I mean Midgar has a bunch of reactors but it also has a huge population. Imagine that they're only somewhat more effective than wind turbines. The more you have, the better, right?
I DON'T KNOW GUYS THIS IS ALL SHAKING MY VIEW ON THE WORLD