Some parents here have children who seemed to learn something without being taught. Do you ever lament that your child could have learned that thing earlier, if only they had someone to teach it to them? If learning things makes the world more interesting, then why delay the process?
My belief is that toddlers and preschoolers are learning all the time. In our culture unfortunately we often define "learning" as about academic learning like reading and math. Much of the important work of these early years involves different kinds of learning - social skills, motor skills, sensory development, development of the imagination, ability to self regulate and cope with emotions, etc. What many people don't seem to realize is later academic success depends in large measure on these nonacademic skills. Ability to direct yourself and cope with frustration as vital to coping with challenging academic material. Upper body muscle helps with handwriting. Imagination is required to be a good writer, etc. etc. etc.
So, no, I don't at all regret that I didn't teach my child academics sooner. I was quite confident academics would come to him easily and they have. It is the other stuff that I knew would be harder and have more risk of derailing his life happiness.