Kenmore 80 series won't dry clothes in one cycle

My dryer no longer dries a load in one cycle, regardless of whether I use a timed cycle or the moisture sensor cycles. Typically, I need to run the load for about 30 minutes after running a full (70 minute) cycle.

I’ve check the exhaust hose and it is clear. I ran the dryer empty for a few minutes and the air coming from the exhaust feels hot enough (i.e., it is amost hot enough to burn your hand).

Any ideas?

I forgot to mention that the drum does spin.