Disruption doesn't come from direct competition. Writing another web browser isn't going to disrupt the market for web browsers. You need a new concept in how we access web-type material. That would disrupt, and wouldn't need much code. Look at Napster et al. They weren't massive but still disrupted the music industry.

The gaming industry still has room for lone coders to make a difference. Many of the top indi games are/were written by individuals (KSP, Minecraft) or by very small groups (Factorio). Sometimes being able to do something leaner, with less code, means you can win ground against the biggest of big guys (City Skylines over SimCity).