Not surprising to see these two teams leading in the Serie A because Juventus in the team they are not racing in tournaments like the Champions League and while they have many good and strong players in the team with a good coach, they also had good times for recovery and Inter Milan is the same team they were in the final match of the last Chmapnis League and they are still in the good format even after losing some palers like Lukaku. I think even Juventus can win the race against Inter Milan if they use the possible opportunities from the mistakes of Inter Milan.
It is only true with Juventus because they don't play in either Champions League, Europa League or Conference League. However it is untrue with Inter Milan because this team actually played in Champions League and they will have two matches in round of 16 against Atletico Madrid, a club from La Liga.
Inter Milan have been showing their strength and unbelievable stable good performances in Serie A even they had to decentralize their player resource for Champions League as well.
Juventus only have to play in Serie A and Coppa Italia and their players have more recovery time than Inter Milan players. In a long season, if Inter Milan continues to go farther in Champions League, it will become big advantage for Juventus.