Bournemouth itself may be small but the surrounding area such as Poole, Wareham, Swanage, Weymouth, Christchurch combined create a large amount of people with a lot of youth.. if you were to look at Bournemouths north stand it is full of people aged 13 - 25! Look at bournemouth town for night life as another example, people come from all over the surrounding areas and get there with ease, again full of youth.
The stadium may not hold 15000 people but it could attract that crowd as the train station is a 5 minute walk from the ground and links to all the local towns pretty easily! The interest is there if the people can fall back in love with the club again.. For most people that are Devon side of Dorset, bmouth is a far more attractive and appealing journey than Southampton because of the poor roads in Dorset. The people that are the Hampshire side of Dorset tend to support Southampton.
On top of this the location of bournemouh would be appealing to most footballers so if it did ever grow, players wouldnt mind moving down here
Boscombe have a massive catchment area and as someone pointed out earlier in the thread a thrieving local football set up, that could match many towns twice it's size. Boscombe's problem is a complete and utter lack of interest in the club for years and years, from the town, it's rich residents and more importantly the local decision makers. They should have moved from Dean Court 30 years ago, down to where the Littledown is now. Weymouth, Poole and that side of the County tend to be more Southampton than Boscombe. I find that most locals are like my family. I moved to Poole from Southampton and my 4 children all support Southampton, despite never having lived there. It's the same with all my mates, their families moved down from London, The midlands ect and they still follow their fathers teams rather than their local team,Boscombe.