Projects should not try to start that big directly. Remember the Linux Kernel first announce: «I’m doing a (free) operating system (just a hobby, won’t be big and professional like gnu) for 386(486) AT clones.». It takes a lot of year to arrive to the project it is now. Another example is Spacemacs, now with close to 10'000 stars on github. It took 2 years of contributions from the author before any external contribution has been made (https://github.com/syl20bnr/spacemacs/graphs/contributors).

But anyway it's priceless to have in mind the big pictures and all steps needed to build a strong community for an open-source project right from the beginning :-)