Google wasn't the first search engine, and Facebook wasn't the first social network.
Peter Thiel in "Zero to One" has a great chapter on "Last-Mover Advantage".
Oh, i just read that one a few days before. Really good point.
If you have a way to improve on the existing product, then absolutely - that can be through the product itself, pricing, service, whatever. Alternatively, if you think it would be educational for you to build, then go ahead.
That is very true, thanks. The educational point is great too.