I think the definition of "good" matters a lot here.

Consider Adobe's Photoshop and Lightroom. Many people (including me) would love to see those supported on Linux, or even better, be out-classed by open-source software, e.g. Gimp and Darktable.

Gimp and Darktable truly are wonderful pieces of software. But they aren't yet compelling enough to cause a mass-migration by professional photographs. Another example would be Microsoft Office vs. LibreOffice.

So you may need to refine your goals a little: Do you want to (a) fill a gap where no viable OSS exists, or (b) help OSS dethrone proprietary software in some category, e.g. Photoshop?

> So a person who is thinking about creating a new open source project can get the idea and start making a alternative?

I cringe when I read that, because I've asked that question many times for myself, and I never ended up following through. I think there's some wisdom in the notion that the best OSS project idea is one that solves a problem you have. Otherwise it's just too hard to really see it through.