The organization I previously worked for has about 500 T1s across the state. Reason being that AT&T will not put MPLS over DSL or consumer fiber. They will run "business fiber" at a cost of about $100,000 per mile. Usually it only has to be a fraction of that, but a typical fiber site install where there is no existing fiber to the building is usually in the $20-$40K range.
Experience with T1s similar in some locations, T1 goes down every time it rains. Thankfully in South and West Texas it doesn't rain much.
Most midsize to larger office buildings around here seem to have a rack in the telco room which Verizon has installed that has fiber feeding it and which provides T1s. I've even seen this equipment installed in the telco room of a warehouse.
But small office buildings that don't get that, they get T1s fed (via HDSL2) from the nearest CO or remote. I guess it depends on the volume of T1s to be supplied to a particular location. Which is why I was surprised to see it in a warehouse.