Strangely enough both the 100 and X66 were profitable in my view. People travelling there for a day out by bus are likely to buy day tickets (or transfers in the case of the X66) to either Newcastle or Gateshead then switch over to the 100 / X66 (depending on location).

Up until recently the X66 ran non stop aside a few journies late at night as the 66 or early in the morning as the 63. These days it now stops at certain locations to pick up extra passengers therefore grabbing those extra fares. But other then that the only two places that the X66 stopped was either interchange at Gateshead or Metrocentre, now we know there isn't housing at the Metrocentre end. And at the Gateshead end, the vast majority would have as previously mentioned gotten the bus or metro from surrounding areas with perhaps a small handful from with Gateshead Town Centre.

The 100 was the same, with 3 City Centre Bus Stops (Greys, Pilgrim and Central) and the Metrocentre Interchange, again maybe a handful of residents within the city centre used it, but again most passengers would have came from other bus routes or the metro.

Thinking about it, whenever new buses came they were heavily branded for the Shopping Centre, the last new buses for either service being the 4 Streetlites for the X66 in 2016. Last time the 100 had brand new buses was 2005. To start off with the services were probably sponsered by the shopping centre to get people there, however as they years went on the sponsership dwindled and the urge to buy new buses for the service is non-exsistant with Go North East and Stagecoach NE putting on well used vehicles that have being used on other routes, and now it's at the point where the service isn't branded.

I don't think the 100 will be returning anytime soon due to the building works around Pilgrim Street unless Stagecoach change the route so it goes anti-clockwise around the City Centre and exits via Gallowgate then down the Boulevard.