Ernesto Valverde's side secured the top-flight crown on Saturday as Lionel Messi's goal sealed a 1-0 win against Levante at Camp Nou to give them an unassailable lead over Atletico Madrid at the top of the table.
Barca have won four of the past five La Liga titles and eight since 2008-09, taking them to 26 in total - just seven behind eternal rivals Real Madrid.
The dominant Madrid side of the 1960s claimed eight league titles in nine years, but Busquets believes Barca's modern-day achievement is unlikely to be surpassed.
"It'll be difficult for anyone to win eight out of 11 league titles again," said the midfielder, a key component of each of those triumphs.
"La Liga has the best teams, who fight for all the European trophies, so it's very difficult to win. What we've achieved is historic.
"Barcelona is a great club but what we've achieved is even greater. It's true that having the best player in the world (Lionel Messi) makes it easier, but the credit belongs to everyone."
Barca now turn their attention to the Champions League semi-finals, with Liverpool visiting Camp Nou on Wednesday, and Busquets is pleased they now have only the Copa del Rey final to distract them domestically.
"Closing out a league or any title is tough, and it was tough [on Saturday]," said the 30-year-old. "But it was time to finish off the league and focus on the Champions League. If we hadn't done that, this week would've been even tougher."
Busquets' boss Ernesto Valverde echoed the midfielder's sentiments, stating on Saturday: "Winning the title with distance and with margin are things that with the competitors we have is difficult.
"We are happy, but we still have challenges ahead."
The Spanish champions welcome Liverpool to Camp Nou on Wednesday for the first leg of their Champions League semi-final showdown, with the hosts tipped as favourites to progress to the final.