"Thus it could be changed at any time."
You mean just like the practice of polygamy in the Mormon Church?
Hmm... I would respectfully disagree with that.
For there are eunuchs who have been so from birth, and there are eunuchs who have been made eunuchs by men, and there are eunuchs who have made themselves eunuchs for the sake of the kingdom of heaven. He who is able to receive this, let him receive it. St. Matthew 9:12
St. Paul also said that he wished all men were like himself, celibate: 1 Cor.7:7-8
I wish that all were as I myself am. But each has his own special gift from God, one of one kind and one of another.
To the unmarried and the widows I say that it is well for them to remain single as I do.
Same chapter he says this in verses 32-33>
I want you to be free from anxieties. The unmarried man is anxious about the affairs of the Lord, how to please the Lord;
But the married man is anxious about worldly affairs, how to please his wife
The Vatican also has an article "The Biblical Foundation of Celibacy: