I can't voice text with iPhone a person without an Apple product

Are you speaking about the short voice recording that you can send, or are you referring to using dictation to convert voice into text and send? If you are referring to the voice recording, you are correct, that cannot be sent to a non-iOS device. It can only be used in iMessage to send to an iOS device.

While you can provide feedback to Apple about this here, www.apple.com/feedback/iphone.html, I believe this restriction has something to do with the difference between iMessage and SMS/MMS which is a cellular function and how non-iOS devices handle texts.