「であったら」。

Was just wondering whether "であったら" would be grammatically correct and sensical; per Google, there are 107 million instances of it out there. This surprises me because I think of ったら forms as "once a situation has come to pass"、as in どうしますか, what will/would you do. 着いたら電話してください, please call when you arrive. 止めたら、どうしようかなぁ。 I wonder what I should do once I quit. So, wouldn't a です form be better expressed as 成る, naru, to become? お金持ちになったら、お金を貸してください, when you're rich (when you've become a wealthy person), please lend me some cash. How would this differ in sense from お金持ちであったら。。。? Would it be something like "if it turns out to be"? 会う予定の人はお金持ちであったら、お金を借りてください, if the man you're planning to meet turns out to be rich, please borrow some money.

It may also have a sense of "if [I] were", as in this 例 from the net: 「もしも私が小鳥であったら」。 So maybe the difference would be that between becoming a bird and having always been a bird. Ie, not "if I suddenly (stopped being a human) and became a bird", but "if I'd been born a bird". 猫であったら、牛乳が好きかなぁ。 I wonder whether I'd like milk if I were a cat. 猫じゃなかったら、牛乳が好きかなぁ。　I wonder whether I'd (still) like milk if I weren't a cat (, thought the cat). If so, would a more formal way be 猫ではなかったら? I'd think not, but hmm. I'll have to keep looking for examples.