The issue is spoke tension. If tension is low enough that spokes get a significant reduction in tension at some point in the wheel's revolution, they will fatigue. If you have tightened all your spokes and replaced some, perhaps your new spokes are not getting fatigued, while your old ones continue to break from the fatigue caused previously. If you replace all the old spokes and increase tension to the appropriate level, you will probably have no more trouble; possibly you need to replace them all at some point. Hard to tell.

While there is such a thing as spoke quality, spoke tension is much much much more important. In most cases a properly tensioned wheel made from cheap spokes will last just as long as a properly tensioned wheel made from expensive spokes.

Inside spokes, outside spokes... yes, it makes a difference to the way fatigue presents itself; but the problem is still fatigue, and fatigue is what's killing your spokes. The rim may suffer, and may be permanently damaged, on account of the spoke problems; but the rim is not the cause of the problem.