the evil is in the details so it really depends on the boundary where the core is defined at, in nginx/mysql's case, the core is large enough for 99% small play

the evil is in the details so it really depends on the boundary where the core is defined at, in nginx/mysql's case, the core is large enough for 99% small players, and the big players are willing to pay and the income is enough to sustain the projects. I somehow feel Kong's core is a bit limited which is how I found out Gravitee.