Maybe if your country is flat as a pancake. If there's hills, then yes, people really can hit 20mph, even with casual bikes.
In NL, the average is ~20kph for muscle-powered bikes on bikes like [1]. Sports bikes like [2] are not usually used in commutes and considered as dangerous as scooters if used at speeds of 20mph. E-bikes legislation takes 25kph as the limit above which the cyclist is required to follow certain extra rules, and of course muscle-powered cyclist reaching that speed should perhaps also be legislated accordingly. The reason it isn't is difficulty of enforcement, but there are people advocating a maximum speed for bike infrastructure [3], at 25pkh.
[1] https://omidbikes.nl/wp-content/uploads/mat-zwart-7.jpg [2] https://s3-wielrennen-xjspucykgif.netdna-ssl.com/welke_wielr... [3] https://www.fietsersbond.nl/nieuws/een-maximum-snelheid-op-h...
Also keep in mind, jogging can cause traumatic injuries. But I agree, biking does pose more risk as you have less control than being on your feet.