What makes you think there was no competition?

The "competition" never been just a different codebase, that's one of the smallest pieces you'd have to actually build if you want to build a product people actually want to buy and use. The magic is basically all around it, multiplied by the code, but you really must have every else down pretty tight before the codebase even start mattering. But once it does matter, it matters a lot, hence the difficult balancing.