This is a routine issue and a major source of wasted energy and increased risk. You've got a blocked vent probably. Wet lint in the vent line is indicative of this issue, the moisture condenses out as the stagnant air cools. It'll be somewhere in your wall or at the roof vent.
Heating elements don't really get less efficient, nor do blowers.

You can test this by running the dryer disconnected from the wall vent, if drying seems to recover you've got a blocked vent. You shouldn't run it this way for long as fine dust does escape the filter and will get all over the house and in your lungs. 1 cycle of a light load is ok, more than that I wouldn't risk.

It needs only to heat and move the moist air out. If you really want to be sure go to your local hardware store and ask them for a temp probe that you can insert into the filter area and watch the temps change. It'll be part of a multimeter set probably, often called a type K sensor and should be pretty inexpensive.
Start it empty on med heat, it'll heat until that temp setting is met and turn off the element. At that point it'll be pulling in room air and should cool about 2 deg F/second. If it takes a long time to get to temp or cool off you've got poor airflow.
If your HOA is paying for this kind of thing then make them handle it all, I love to charge building maintenance my $80 diag fee to tell them to do a basic maintenance task and call someone to clean their dryer vents.