I don’t understand. Arriva could not make services work financially in mid Cheshire and after years of decline packed it in. Arriva would cut loss making services (eg 82,130) and D&G were able to jump in with council subsidies. Most of the funded services went to D&G who undercut Arriva to obtain them. Now we have brand new buses everywhere. Are D&G favoured by the councils? You could kind of see how D&G operated in the past - low wages and old buses keeping costs down, but how can they suddenly afford brand new everywhere?
Keeping costs down is less to do with how old the buses were (they may not cost as much to buy but you spend more on maintenance and depending on age comparisons you may find fuel savings with the newer buses), it is how streamlined the company is behind the scenes and what margins you are prepared to work to. Arriva being a big group company would be looking for bigger margins and would have had more management & admin staff than someone like D&G would employ so a route that is barely breaking even for a big group operator may be comfortably commercial for a small operator with less head office & admin costs to cover. There will also be a change in vehicle deployment philosophy when you are the main operator to that you would do as secondary operator.
In terms of the new buses, in the past Centrebus & D&G have been able to source decent numbers of relatively young secondhand purchases but recently there has been a dearth of such vehicles on the secondhand market (& what there has been has often been snatched up by big operators as soon as they become available) so if you can get a decent deal then going new is probably all that is on offer. Before this big batch of new buses turned up D&G had an ageing fleet that needed replacing so someone needed to get new buses, Centrebus hasn't seen the same level of investment as they had a younger fleet at the start.
You can also see that, thanks to BSIP, some of the councils have been quite pro-active in promoting and developing their commercial networks (particularly the marginal ones) as well as their fully supported networks and new buses are often the operator contribution to these developments. Stoke appears to have been quite proactive and quite a lot of D&Gs new buses have gone there with route branding which may provide some explanation. Both Centrebus & D&G seem to have gone through periods of investment and then periods of limited investment, the couple of years before COVID (from 2017) were low investment whilst before that saw quite a few new buses (Particularly at Centrebus starting around 2013) and in the last couple of years it has picked up again. Also the group appears to have been quite successful in winning new work and as secondhand vehicles aren't as easily available as they were then again new vehicles coming from stock often have to be taken to provide the vehicles (either directly or indirectly via cascades)
