• cPanel moving to per account billing (although they still allow unlimited subdomains)
• WHMCS moving to per user billing (part of the cPanel’s parent company)
• Plesk falling in the same bucket as above (suprisingly they haven’t yet taken up the user model, although theirs has been following the domain model since ages)

One triend that indeed seems to be changing is the once apon a time “unlimited features” keyword being lacked in the current new adverts. I more feel it could be something to do with the industry more pushing SSD and NvMEs which are not as cheap as HDDs, while the end-users hardly noticing the difference, or the reasons could be something else.

Personally i think, there was a trend when everyone thought that except for the price-point, there is no other point left in selling a traditional shared hosting package, so everyone simply jumped to that bandwagon to sell unlimited hosting packages and now are slowly recovring from it that afterall in this world, nothing can indeed be unlimited! There will be limits, may-it be the often trending inodelimits to the bandwidth limits on a unlimited disk space to many other things.

In your case it just tuned about to be the subdomain limits, which would have earlier fallen into the “unlimited features” param where subdomains were features