I don't disagree completely but the impact has not yet seen! It's too early to conclude anything and we are just assuming that would happen. However, if the price increases, that won't be the case and miners will still be profitable with less block reward. This quitting thing would only come to reality if we see bitcoin price decreasing, otherwise not! If you see the bitcoin hash rate chart, you will see that the hash rate has actually increased gradually over the past 60 days, which is a sign that miners are also ramping up to deal with the less block reward. Let's wait for at least 1 week to conclude anything at all!