It all comes down to the film's structure. Modern films like T-Max and Delta use tabular grain. The structure is very even, something that isn't in traditional films.
Normally, the silver grains are of random sizes, something which gives a softer look to the image.
You may wish to know that Kodak Tmax films aren't wholly T grain, they are hybrid films with flat grains in the two upper layers and 3D grains (Kodak speak for cubic) in the layers below.
The upper layers of T grain are poly-disperse that is they vary in size and shape while the two lower cubic forms are mono-disperse (same size) in a traditional two layer dual speed configuration.
Iford Delta uses a very different method whilst the grains are flat they are 'epitaxial' that is they are of the same size and shape have 'ears' at each corner which are sensitivity specks.
Fuji Acros is another hybrid film that uses epitaxial grains and cubic layers in stacks.
All the 'Traditional' films are very different from the films of the 1930's in that they are all mono-disperse cubic forms that have different sized records in layers to give them more latitude.
The last film marketed with 'fat' grains that is many polydisperse layers was Verichrome pan, these types of films were easy to process and gave a wonderful glow.
In my opinion, lighting and possibly something not mentioned yet which is lens rendering are the key factors.
