Ecommerce pragmatism or defeat?

On Black Friday, last year, less than 50% of ecommerce retailers offered next day deliveries - as opposed to greater than 80% offering a next day option on normal trading days (one of 5 key research findings in an IMRG and Magento white paper '5 Things We Learnt From Black Friday 2019' )
So, is this a disappointing example of brands diluting their customer experience and making it inconsistent in favour of a margin-reducing sales frenzy, or just sensible pragmatism?
What do you think?
Personally, I'd say it's pragmatism. Retailers don't control the delivery carrier networks and we all know those networks are severely stressed by November and the Black Friday period and often at breaking point in the run-up to Christmas. Nearly every customer-facing business is part of a complex infrastructure of suppliers and at times it makes sense to go with the flow. Added to which, the majority of discount-driven purchases over Black Friday are less likely to be focused on speed of receipt than size of savings.
However, its not clear from the IMRG & Magento research if Amazon also restricted its next day delivery options over Black Friday....