As someone who biked daily for transportation and recreation for years, I can tell you it doesn't take any miracle to do it in street clothes.

[David Richerby][1] already mentioned that most practical bike trips are short. Mine were usually 10-20 minutes. But many times I've gone on recreational rides of 2-4 hours. And I've never owned any special "biking clothes". The most I ever thought about  clothing was when my jeans started getting worn out from occasional encounters with the gears!

It probably depends on the person, but many feel perfectly fine in street clothes.


  [1]: https://bicycles.stackexchange.com/users/13174/david-richerby