The choice we had when we made it, and that we still have:
We give plain text boxes and phone keyboards love it, but you lose some functionality that is built in on desktops (quoting by highlighting text)
We give richer text boxes and phones all hate it, but we can retain all of the functionality
We chose the former.
We just wanted the text boxes to work, even when on a weak signal, and without you having to wait for it. We also wanted it to take advantage of your phone keyboard as much as possible, which meant just saying to your phone "I'm a text box, gimme text".
It's an Apple thing. The quote above was done on WP10 in pretty much the same way as I do it on the desk top machine, highlight text to quote and hit reply.
It requires manual intervention, copy and paste.
The choice we had when we made it, and that we still have:
We chose the former.
We just wanted the text boxes to work, even when on a weak signal, and without you having to wait for it. We also wanted it to take advantage of your phone keyboard as much as possible, which meant just saying to your phone "I'm a text box, gimme text".
It works, lack of quoting is a minor thing.