Ronaldo departed for the Serie A champions in the summer after establishing himself as one of Madrid's greatest ever players.
The 33-year-old is the top scorer in the history of Real Madrid, having netted an incredible 450 goals in 436 games with the club.
Replacing that level of producation was never going to be easy, but Madrid only managed to bring in their former striker Marcelo Diaz and teenager Vinicius Jr. as summer attacking reinforcements.
Boluda, who was Madrid president in 2009 – the year Ronaldo arrived from Manchester United – expressed his surprise that the Blancos did not have a better plan in place to replace Ronaldo's production.
"I will not be the one to add fuel to the fire, I do not want to delve into the wound, but Cristiano's 50 goals have come to nothing and that is a reality," Boluda told AS.
When asked if he was surprised to see Madrid sell Ronaldo, Boluda said: "Very much, but mostly because there was no alternative plan.
"These things have to be done with a program of two or three years. It's like a company when you decide to relieve the entire board of directors. It's not something you can do overnight.
"Cristiano has gone, the rest are left and nothing happens ... Well, what is happening is happening, which was inevitable."
While Ronaldo has started out his Juve career well, scoring 15 goals in all competitions thus far, his former side have struggled in his absence.
The Blancos have already sacked one manager this season, Julen Lopetegui, and his replacement Santiago Solari is under pressure with the Argentine achieving mixed results since taking over in October.