The fact that it's hard or inconvenient to make one doesn't change the fact that we have to. Stop being lazy and focus on making or improving a free open-source engine so you can make games.

You seem to underestimate the immense amount of work a good quality engine requires. It's not about being lazy or having some neglectable inconveniences. For a lot of, especially smaller, developers this is a matter of financial survival.

Open source is cool, but requires dedicated regular contributors. The more work there is to do, the more important this and the number of contributors is. And there are not enough good engineers who like to dedicate their free time for such unpaid work. This just doesn't work very well with such a capitalistic economy system that we have now.