First of all: the ASA speed of a film is part of the ISO speed. An ASA 100 film would have ISO 100/21° where the 21° is the DIN standard film sensitivity.
Basically the ISO speed of film and DSLRs are comparable. In film days the ISO speed of a film had a direct relationship to the size of the film-grain. An ISO 25 Kodachrome did have a much finer grain than the ISO 200 Kodachrome and most of the time lower ISO did also mean higher resolution.
With digital the relationship of grain and ISO is gone. A 16 MP camera stays 16 MP no matter what ISO you set it to. Of course things like image noise increase when you increase the ISO speed of the sensor.
And the low end? I think if a sensor does not perform visibly better at ISO 50 than it does at ISO 200 why not leave it at ISO 200?
The beauty of film was, that you could use an old camera and still use the latest film. If you do not care about high speed film you can simply use the ISO 50 Velvia (I think this is the Fuji film you referred to) and if you needed some high speed film you could load your camera with an ISO 3200 b&w film and push it to 6400 or higher.
And for your decision: I recommend to try to get a camera for some test shots and have a look at the images. If they are too noisy for your taste then you will need to stay with film. If you need the low ISO for long exposure times to blur motion you can still use ND filters.
Btw: most cameras also offer lower settings than the base ISO, but I never used them. I have to admit that I also was a little worried that the cameras start at ISO 200 as I had the same comparison with film grain. But this is really nothing to worry about. I use a D700 and the image quality at high ISO is so much better than it was with higher speed films.
So don't worry about the high base ISO, get some test shots (if you can't get a camera have a look at the Internet, there are plenty of test images from all types of cameras) and judge yourself.