If you're making software, you can achieve market penetration in an afternoon by signing a deal to bundle your app on a phone or social media platform.

This is relevant to only a small segment of the market. A substantial majority of software development, even VC-funded software development, isn't something that can meaningfully be sold as a consumer-facing phone app.

That signature usually takes years of preparation and negotiation...

For almost everyome, that's not an option.