Winding your own transformer is really not that big of a deal. Especially if you work in R&D as a power electronics engineer. No one waits for the custom transformer to be delivered to your bench when you were designing a new power supply.
For high power stuff though, you need some equipment to do that since copper will hard to bend neatly.
For high power stuff though, you need some equipment to do that since copper will hard to bend neatly.