37Signals was an avowedly Mac-centric shop until Apple's move to kill home screen web apps led the firm and its very-public-facing co-founder, David Heinemeier Hansson, to declare a "Return to Windows," followed by a stew of Windows/Mac/Linux.

After 37Signals waged a public battle with Apple over its App Store subscription policies, the outcry helped nudge Apple.

Now it seems that 37Signals has pulled its seven cloud-based apps off Amazon Web Services over an argument over absurd premiums for defence against "wild swings or towering peaks in usage."

When the decision was announced, Hansson wrote that 37Signals was expected to save $7 million over five years by buying more than $600,000 worth of Dell server gear and hosting its apps.

Now Hansson had an update: it's more like $10 million, although it cost $800,000 in gear.

By squeezing more hardware into existing racks and power allowances, estimating seven years' life for that hardware, and eventually transferring its 10 petabytes of S3 storage into a dual-DC Pure Storage flash array, 37Signals expects to save money, run faster, and have more storage available.

"The motto of the 2010s and early 2020s -- all-cloud, everything, all the time -- seems to have peaked finally," Hansson writes. "And thank heavens for that!"

He adds the caveat that companies with "enormous fluctuations in load” and those in early or uncertain stages still have a place in the cloud.