Decrease
The more popular and acceptable streaming has become, the more our average attendance has increased, despite the teams performance getting worse every year.
I don't believe streaming significantly impacts attendances. There's no evidence to support it and the overwhelming majority stream away games they can't get to, where we continue to sell out and have one of the best away followings in the country.
On the contrary, it doesn't take a genius to realise if you half the amount of games the average fan is able to see, the average fan will become less emotionally invested and therefore more likely to jack in.
Our attendances will drop regardless because of relegation and there'll be a good chunk on either side of the fence - some who haven't renewed but will return if they have something to believe in, and some who have but are very close to their tipping point or have only renewed out of habit. At least it they can stream games they're still doing something at 3pm on a Saturday, the last thing you want is fans to find something better to do.
It took years for attendances to recover after the 19 point season because fans got sick and gave up out of protest then found better ways to spend Saturday afternoons.
I bet we'd have got higher crowds if streaming was around then and fans still had an emotional attachment to the team.