Those are exceptions. Like I said almost all the 35-40 times I've seen him since 1991 have been in smaller sized venues. Even in 1995 on the Boxers-tour, at the height of Britpop, he was playing small venues, and those were perhaps his best ever shows.
He is not the sort of artist for festivals or huge arena's. He is too idiosyncratic and too much of an outsider for that.
And look at the setlists, you can't play too many b-sides or album tracks on festivals or on big stages.
If he would like it bigger, as you suggest, he would cater for those kind of audiences and do a Greatest Hits or even Smiths-tour, like Liam is doing now with his Oasis-themed tour, but he doesn't and will not do so.