Some web designers and operators believe a well-designed web site should keep visitors on site longer. A new site with a slower layout, can accomplish this by not allowing the visitor to efficiently move on thru. In short, "follow the money trail".
The current legacy DPR website is one of kind, which has clearly stood the test of time. It still is the most user friendly and has the most efficient flow unmatched by any recent forum-based sites. Trashing this time proven site, for yet to be explained in any real detail, shows no logic and raises more questions than answers.
This strategy is common in retail stores and websites. It's all about increasing "dwell time." Studies have shown that increasing the dwell time in a store by 1% increases the sales by over 1%. That's the reason of the in isle display one has to navigate in your local grocery. That's the reason for frequently rearranging items on the shelves. Slow people down and they will spend more and more money.
For example in the old days where music came on vinyl and later CD's in record stores, the stores were laid out to incentive the customer to browse. The longer you were there the more likely you would find something you just had to have, say a copy of the first release of Chicago, anthology of Miles Davis, etc. The longer you send in a large camera store - the more likely you are to find something you "just have to have."
https://cloudcovermusic.com/brick-and-mortar-guide/increase-dwell-time
Dwell time is also important to web based businesses.
https://www.salishseaconsulting.com/blog/what-is-dwell-time/
On websites it seems to be important in the Google assessment of your web site in their ranking of responses. Why is Google ranking important - it ties to what a website owner can charge for advertising.
https://tinyfrog.com/boost-website-dwell-time/
This is a well established practice in marketing. Did it play any role in DPR's hosting S/W decision - only those that made the selection and management know.