Injury is an increase in Lukaku's performance getting worse but actually as long as he is not injured it is also a little difficult for Lukaku's performance because indeed for several seasons after his good performance at Inter and Lukaku his performance worsened again at Chelsea.
Inter Milan rescued Lukaku from Manchester United and gave him a second chance to revise his career. His first chance is in West Brom after a first failure in Chelsea when he was very young. After succeeded in Inter Milan, he returned to Premier League with Chelsea and failed a second time there. Inter Milan put out their hands a second time and gave Lukaku a third chance to revise his career. In the last season, Lukaku did not show signals that he can revise his career again in Inter Milan.
I think saying Inter saved Lukaku is too harsh in this case because when he was bought from Manchester United actually he was also quite good it's just that there were some problems and couldn't follow the scheme that was carried out by Ole at that time so he decided to leave and when at Inter he was very trusted Conte and supported by the full support of other players made his mentality better and found his performance.
Actually I think it's an old story and it has nothing to do with the present because it's gone too far. Currently, the fact is that under Inzaghi's tutelage with injury problems, Lukaku's performance has dropped dramatically and Inter were also initially a little hesitant to make Lukaku permanent but it seems they have changed their minds since the price has dropped dramatically at this time.
The latest news seems to be that Inter will sell off several young players such as Samuele Mulattieri, Facundo Colidio, Darian Males, Martin Satriano, Sebastiano Esposito and Eddie Salcedo. for the plan to buy Lukaku because they think that Lukaku is suitable to partner Lautaro.
If their plan is like that, I disagree with that plan. They must emphasize on growing young players rather than selling them and using not cheap cost to buy Lukaku. Sacrificing some young players to exchange a player like Lukaku who is at
his 30 yr-old is something not smart.
Regardless of the pros and cons but it looks like Inter will try this out, the reason is simple apart from making some adjustments and downsizing to their squad they still need money to get players in instantly.
Indeed, I also agree with what you say because this can hinder their rate of regeneration but when they say that it is difficult to change, I think because they have authority over the club.