Hard to disagree with your thinking ergo, not that I'm looking to!
> I know how much you've poured into Mojeek
I've put effort in for a couple of years. Almost all credit goes to its founder. Learning so much from him TBH.
> Google is currently the one that is most convenient,
Indeed. If there were 3 or 4 unique indexes and complementary meta search engines then it'd be more interesting IMO. Bing which I sparingly use does seem quite comparable to Google, at least for English stuff that I search for. If we got to a stage where searches are fired into a round-robin search bar with the option of enabling/disabling participants in the round-robin, that could be interesting. As long as you deem them quality enough, it'll offer a more diverse opinion without specific-algo-rules squashing a dimension of the results. I do see a fair few referers from those kind of round-robin search options, sites that tend to focus on privacy.
Agree that it'd be hard to out-G G given their history, expertise and resources. We focus on European languages ATM as there's plenty to index there already.
Ultimately if there's a diversity of indexes, algos and UIs to scour the web, more of it is available by search.