Jules, there are many parish councils that meet in village halls, the wifi is shonky or non-existent and the precept is so small that to purchase the AV equipment required would be a considerable % increase on the precept. Plus if they only meet 4 times a year, then the investment is perhaps considered to be not required (especially if the parish has less than 500 residents, for example).
The high tiers have council buildings and council chambers which are easier to set up and perhaps better designed for broadcast.