Subjuntivo presente in Rioplatense

Hi!

As we know, Rioplatense Spanish consequently uses the VOS conjugation, with the expections of subjuntivo presente and pretérito indefinido, in which case it uses the TÚ forms.

Anybody knows the history behind this?

By the way, the VOS conjugation in the subjuntivo presente is not completely lost. It's still quite usual to hear "No empecés!", "No digás nada!", "No seás tonto!", etc.

Gracias!

Subjuntivo is optional, and it sounds a bit elegant, but in more colloquial styles it is often not used, optional is the best thing to use here.

Sorry it's the other way around:

Subjuntivo is optional, and it sounds a bit LESS elegant/formal, but in more colloquial styles it is often used, optional is the best thing to use here. Youngsters seem to use more and more VOS subjuntivo, it's less and less condamned than it used to be.

Muchas gracias!