Why Paul Ryan is leaving

I've just assumed Ryan is stepping down so he won't have to be humiliated by losing to Randy Bryce in November.

Cenk Uyger of The Young Turks in this video lays out what he says are the top four reasons:

4.  The stress of working with Trump (which Cenk says is only a very small percentage of the reason);
3.  To cash in by getting a job from one of the corporations to whom he just delivered huge tax cuts, and then return to government (revolving door);
2.  To avoid being Speaker when the referral for impeachment comes;
1.  To avoid being humiliated by losing to Randy Bryce in November.