That is more than a little misleading. Heartland pays 50 cents per mile in specific areas only (east coast runs are one such area).
In addition, it is nearly impossible to average 55 mph due to traffic, stopping and starting, etc.. That also fails to take into account the layover time, waiting time and other variables that count against driving time. Some companies do offer layover pay, but that is generally paid only after you’ve “donated: two hours to the company. Even then, the pay is minimal.
Now that, I’ll believe. Some areas should get paid more per mile than others. I-80 through Iowa and Nebraska is pretty smooth running. Sometimes the hardest part there is just staying awake.