>This is obviously false. First, employers can't just stop giving raises. Raises are governed by law and by collective agreements (although they are often below inflation).
I don't know about Argentina specifically, but in many countries unions negotiate salary raise percentages for the whole sector. If the country follows universal collective bargaining, this may also be a binding minimum raise for non-unionized employees in the same sector, even in companies that aren't members of the trade union that bargained the deal.