Rebranding another of the idiocies of franchising.
It has to be said though that the nationalised railways were hardly immune from periodic rebranding.
The British Railways regions had their distinct brands. WR,
SR‡ etc. With differing liveries. With the advent of British Rail some uniformity was achieved, but there were still differences in liveries and numerous regional variations in brands. Then there was sectorisation. Inter-City, Regional Railways, ScotRail, Network SouthEast. All branded distinctively different.
Yes, there's more brands these days, but the periods of change aren't much different to nationalised days.
And if you want to go back to pre-grouping in the 1920s, there were literally
hundreds of 'brands'.
The network as a whole still hangs on to the
BR▸ 'double arrow', though. And long may that continue.