Psychological impact of a more successful sibling?

There are two different ways to look at this.

Having a very high achieving older sibling could very well spur you on, and make you determined to do well, and even out-do them if you will.

Or It could have the completely opposite effect, and just make you feel like you're not worthwhile, you'll never amount to anything etc.

But just remember money doesn't mean happiness. Sure they might have a more successful career, but who has a more successful life ?

it should have no effect, unless you have low self esteem

You have your life, they have theirs and their success is their business

I have 3 sons, the eldest has a very successful business and plenty money, it has no effect at all

on my other two sons as they are too busy living their own lives