Why Don't You Make Your OWN Game Engine?

I've been asking around, trying to find out why people avoid game engine development. There are a lot of misconceptions and concerns that can be easily addressed. So why don't you give it a go?

Content
0:00 Introduction
1:30 Getting Into The Right Mindset
2:53 Time It Takes To Develop
4:12 Technical Knowhow Needed
5:43 Comparisons Against Pre-established Engines