It was quite similar in France. It was a step before privatisation, true, but the final step would have been the re-nationalisation of the infrastructure and maintenance branch, in a usual “privatise the profits and socialise the losses” that the European Commission seems to so love. Because efficiencies, or something.
It's been separated into many subsidiaries in preparation for a privatisation. It never happened and while subsidiaries like Schenker work quite well and drive profits, others like those responsible for network or train maintenance create only costs and have been neglected. This results in delays in your daily experience with DB. DB's "punctuality" or the lack of it is actually a running gag here in Germany.
tl;nr: mismanagement.