inter basically had one (or two, no idea about how and if their rosters changed during those years) great generation(s), which got them to 4 CL finals in 8 years, in the 60s and early 70s. Obviously the competition wasnt as strong as it is now due to format and who got to play in it (they played Everton, Monaco, Partizan, Dortmund, Real, Dinamo Bucurest, Rangers, Liverpool, Benfica, Torpedo Moscow, Vasas Budapest, Real, CSKA Sofia, Celtic, AEK Athens, Gladbach, Standard Liege, Celtic, Ajax in their 4 trips to the final those years). Then the post calciopoli generation managed to win a CL. Other than that, they didnt have any noticable CL success during their history. If we look at all european competitions, they had some success in the 90s golden age of italian football when they couldnt sniff at the scudetto due to Milans and our dominance, and had to play in UEFA cup a lot, winning it 3 times and playing in the final once more.
So basically, they were really good at 3 points in their history in europe, 60s, 90s and 2010. We were much more consistent in euro cups overall, especially from 70s till mid 2000s