I wonder if the timeline represents the way smaller venues book their shows?
In some measure yes. But it is also woefully incomplete in my opinion. I've just put my post code (zip code) in and it has found exactly 7 events in the next 8 weeks.
I can 100% guarantee you that is not correct, you will find any number of live events on at local pubs and social clubs. But they are the sort (mainly) when you turn up on the door and pay, or are only ticketed direct with the venue.
On August Bank Holiday weekend we have two music festivals in my town on successive days- not on there. The second one is in a very public venue in the middle of town (organised by our local theatre)- not a pub or a social club. The first, on 29 August, is just being promoted locally, but anyone with local knowledge is more than welcome to attend.
This reminds me of a question we had some time ago about a music events website in part of WA state, I'm 5,000 miles away but when I looked at the site, I thought 'is that it?', even I know a ton more events and regular venues than that, from general knowledge, not even following their local music scene.