I think Percy (he writes all the software for this board) will probably someday add buttons for that, but when, is of course hard to say.
From what I recall, the buttons are absent on purpose, to avoid people having quotes within quotes within quotes within....etc. which can quickly clutter a thread.
Probably a wise decision.
Yes, that's part of it. The big problem was that in any discussion involving long posts, which are common here, too often people would click the reply/quote button without trimming any text, and after a chain of just a few replies messages would quickly become prohibitively long.
The reply/quote button is disabled through the control panel, but I've just enabled it so people can prove they're more disciplined now, but I'm sure Adminnemooseus will disable it again at the first abuse he sees.
A planned feature is to be able to select text, then click a button to have it automatically quoted.
And, with minimal effort it can be used.
Percy, also consider a limit of say three or four nested quotes.
Anyone so limited that they can only spell a word one way is severely handicapped!