same on XPS 13 9310

Not surprised.  I think there is an issue with the glue used. I have 4 year support and accident warranty.  But DELL CARE say consumable therefore not covered. Well, the problem isn't the rubber wearing out. The problem is the manufacturing of the laptop. Further, these parts are so consumable that you can't buy them, unless you buy a 'consumable' lower cover! Yup, they are integral to the cover and cannot be bought separately. So they aren't a consumable part. But DELL would rather sell warranties and then customers on a minor part than keep customer loyalty and take moral responsibility for workmanship.

Yes I have this problem too, Dell XPS9720. The machine gets hot and the strips fall off. Dell refused to do anything about it saying the strips were 'wear and tear'. After 4 months occasional use in a domestic environment I find that insulting and disingenuous. I have found that superglue works, to a degree. Contact adhesive doesn't. Remove the remnants of  what looks like double sided tape from the rubber strip first.

On the positive seide they did replace the touchscreen under warranty due to a 'ghosting' issue (uncommanded actions happening!). I won't be buying another Dell.

About Rubber Feet Strip Replacement

Dell recommend you change the chassis (Base) for the model Dell XPS 17 9700 the part number:
RTGNV. 

This is a dumb solution, but this was the answer that I got twice. 

Exactly the same problem...Dell replaced the bottom plate first time, but it has of course happened again.

Do they employ technicians and engineers? Hopeless flaw. No further Dell's for us, and we are not the only ones..the more we talk to people about it the more we hear about the problem and how it is turning people away from this brand.

Did anyone ever figure this out? I need one for my XPS 17 9730

Let's be honest here. The 'solution' that will save time and frustration is to just go to a harware store and buy some thin, stick-on rubber pads. 

No. I had just paid a large amount of money for a high end laptop. The touchscreen screen failed within weeks. That was replaced under warranty. Then the rubber strips all peeled off because the heat from the machine softened the adhesive they’d used. Poor design. Dell refused to do anything about it. I was not prepared to do something like the ugly botch job you suggested to a new machine. I bought appropriately sized square section rubber strip from Aliexpress and glued it into the slots with superglue. It looks better than the original, works just as well and is still in place years later.

Thank you for your input.

I can add my two cents to this. Same issue on my 9730 and have same issue on previous 15 inch XPS. On the older one I glued back on myself with superglue and worked fine. On my newer machine I thought I would reach out on warranty. Same story as others here that it is wear and tear. Surely this is a know issue for years now with heat softening the glue. Horrible support from Dell. I have now moved to Lenovo for latest laptop purchases for staff. Seems to be pretty common these days to screw the customer to save a few cents.