Technically they are not 'wild' phals. They are properly "species" Phalaenopsis.
The better the culture, the better they grow. A plant with 4-6, 3-4" wide leaves and 8-10" long would be a nice sized plant.
They don't keep growing leaf after leaf. Phalaenopsis do not carry 12, 15 or 20 leaves.They generally mature and maintain four to six leaves. They don't last forever. Again, the better the culture, the longer the leaves last.
How does one know if the culture is good?? That is the million dollar question. With Phalaenopsis every new leaf should be as large, or slightly larger then the one that preceded it. If each leaf produced is slightly smaller to significantly smaller, that is not good! That is a sure sign that something is wrong with their culture.
And with Phalaenopsis they should be repotted into fresh media every 2 years typically.