Thousands?? Is there really nothing better to do in Melksham??
Do you work for
FGW▸ by any chance, 000000? They consistently underestimate the size of the town and level of support in and around Melksham as well, judging by the truly appalling rail "service" they provide.
The carnival procession and associated events (stalls, entertainments, and in the evening live music and fireworks) regularly attracts between five and seven thousand people throughout the course of the day - more if the weather's good, as it was last year.
Considering that Melksham has a population of around 21,000 that's not actually a bad turnout -although it's nothing compared to another town on the FGW network, Bridgwater, which typically sees around 150,000 people attending their carnival. Bridgwater has a population of around 36,000 - I daresay you'd accuse them too of "having nothing better to do".
Melksham's annual carnival would no doubt see an even bigger turnout were there trains laid on to bring people into the town (conveniently, the carnival procession begins just a short walk away from Melksham station), but requests to FGW have to date fallen on deaf ears.
The principle difference between Melksham's Party in the Park and similar events occasionally staged in nearby Trowbridge and Chippenham incidentally is that the latter's are funded by and managed by their respective town councils and paid for by residents via their council tax, whereas Melksham's is not supported or underwritten in any way by the council - it's entirely staffed, funded and run by volunteers.