This.

I always sort of hoped that Apple would either enter the market at some point or acquire DuckDuckGo and try to build out to a larger user base. I realise this is pretty unrealistic, as I'm sure there are far more people out there who would much prefer DDG to remain independent of a megacorp.

I assumed the reason Apple haven't entered the market is that there's likely no way to make money at it without becoming Google, so it would cause them to have two diametrically opposed privacy stances in their business (and because they'd have a long road to build a worthy competitor).