High probability. To compare with UK spain also has separatists movements. Many believe that the monarchy is the only thing between us and disaster. There are no republican movements in parliament. The main left group is republican but behaves in government as pro monarchist. The right party does the opposite. Our syrizia party is republican but tries to downplay it. The other new right party is promonarchist.
Most do not have much love for them but we only had had peace and democracy since JC was in power so that is an emotional point that for older generation counts.
Also it shows that the establisment prefers the monarchy as they made JC abdicate so the transition with the next king would be easier. Most newspapers are pro Felipe. Not many criticism to him. Sometimes against Letizia but not much either and if there is it is more superficial than anything.
If the journos started talking maybe they would last a month. But there is no interest and the fear of breaking the country due to republican ideals is a big hurdle.
The bourbon dinasty has been a disaster to this country and every two generations they have been exiled. But although I would like to see it I do not have much hope.
Even now with one of their best friends involved in many corrusption cases the press downplays their relationship. https://www.theguardian.com/world/2016/mar/09/spains-monarchy-banking-scandal-queen-letizia
Maybe we will know the whole stroy when they are old and they want to sell the new generation the same way they did with Felipe.