> The value gained from cheating in a video game is low enough

Many people made serious money botting MMORPGs and selling gold. It's so prevalent it accelerates the inflation of the in-game currency.

If people make it too difficult to hook into the client, cheat developers can always reverse engineer the network protocol and make their own custom client. This bypasses all client-side annoyances. They might even create a headless client that can be run on servers.