One of the main reasons dont forget is that the Bravo is out of production and has been for some time. With the tight purse strings on manufacturing Fiats now and the fact that huge effort went into the production of the Stilo, there weren't many parts made for nearly 2 years. Also, Italy closes for the summer - may be lazy to you but it gets my vote of our 3 days bank holidays! So if you drive a car that isn't the current model, dont expect the manufacturers to have the parts instantly, especially Italian manufacturers. Also, not all the parts are made in Italy so they have to get there first!
Once you go into classic cars, it actually can get easier as I have found with my Jag. There were only 238 made of mine, but I have found a supplier who can get me in the region of 95% of parts within a week if not next day.
Fiat Bravo HGT155
Jagaur XJR-S 6.0 V12
http://www.bravo-guide.co.uk THE Fiat Bravo site