I'm not so sure that short rest is a thing that falls back to those rules though. It's been obvious that short rests are going to be getting some changes for a while now since they started pb/long rest stuff. Adding in a glossary entry for long rest that mentions failing over to short rests without including a short rest entry as well doesn't give the 2014 short rest a strong footing. If the only benefits of a short rt rest is the recovery of abilities that say they recover on short rests that is covered by the playtest rules. We might ultimately see a regression to include the old short rest rules in a future packet but the short rest omission was noted in the first packet as well so the omission is probably not one of mere chance accident.This is just wrong.
The playtest has a general rule: what is not defined in the playtest is the same as in the 2014 PHB, so youbcan just start a short rest as normal...
It doesn't have a glossary entry for short rest but it does say what the benefits are in eaxh ability that says it recovers on a short restThe rules do not say that and the part you quoted does not say that. What they say is you get the benefits of a short rest if you start a long rest. It does not say that is what a short rest is. Further, since it does not define a short rest anywhere in that document, to include what the "benefits" are, it is relying on the current definition of what a short rest is.
Finally this interpretation would mean it is impossible to do a short rest within 16 hours of your last short rest and I am quite certain that is not RAI.
There is no reason for that sixteen hour thing though. You can't benefit from a "long" rest more than once in a 24 hour period but a long rest that is ended after an hour gives the benefits of a short rest & is not subject to the once per 24 hour rule
Like the inclusion of blindsense while excluding dark vision I think short rests are probably a thing that they aren't quite certain about or not yet ready to put out. Either way though there is no reason not to assume that a discrete short rest glossary entry couldn't also include a lose inspiration at the start footnote.I also don't read that as changing how short rests work. I definitely don't think that is WotC's intent. It would be a really convoluted design choice. I think if they wanted to change short rests to only being a thing when long rests are interrupted they would state that directly.
Edit: here is the PHB definition which as far as I can see still stands:
"A short rest is a period of downtime, at least 1 hour long, during which a character does nothing more strenuous than eating, drinking, reading, and tending to wounds."