I appears you don't want to see it...or reading might be a serious problem for you.
You keep mixing apples and peers.
There is a difference between having an android device and using Whatsapp.
The same holds through for Apple owners, not all use iMessage, for instance China is the biggest iPhone market, but almost everybody there uses Wechat.
You cannot make a 1-on-1 comparison.
Android holds 90% of the DEVICE marketshare, Apple holds 10% of the DEVICE Marketshare.
With different message platforms (WA, Wechat, Line, Viber, etc).
Whatsapp and Wechat are the biggest with about 2.4 billion users taking about half the messaging market.
Apple has 10% market share on devices but iMessage produces only 5% of the total message volume.
So around 50% of the messages on iDevices is sent via other apps.
So in whichever way to you try to twist it, your baseless assumption don't add up.
And to go back to what you actually said:
"iMessage, or lack thereof anything even close to comparable. That's the #1 reason I stick with iPhone. If Android or a third party had something that was universal that even came close, I'd be the first to jump ship from iOS to Android."
We established that there are several alternatives but you don't (want) use them, that is up to you but you statement is completely debunked. There was no other discussion point.
Now that we established that lets go back ontopic, yes it still is a very long time without a JB.