Wrong. Mark Cerny said that compatible drives will need to be 7 Gbps to deal with the processing overhead of the PS5 storage subsystem.
NAND chips decrease in performance as heat increases so you better believe every one of these things will have a heatsink.
This is what a 7 GBps NVME drive looks like:
If you have a source for where he's said 7GB/s is required then I'd like to see it. Right now this is what I'm going off:
No PCIe 3.0 drive can hit the required speed of 5.5GB/s, as they are capped at 3.5GB/s. However, the first PCIe 4.0 M.2 drives have now hit the market, and we're seeing 4 to 5GB/s speeds. By year's end, I expect there will be drives hitting 7GB/s.
Unlike Xbox Series X, PlayStation 5 has a regular NVMe SSD slot for expansion. However, compatible M.2 drives have to be validated.
wccftech.com
Just because he references 7GB/s as an example, it doesn't make it the requirement. He also said the speed would possibly need to be need to be a "little more" than 5.5GB/s but nowhere does he say 7 is the requirement.
Regarding heat, there are a number of factors at play but the primary ways these drives get too hot is by hammering them with writes, and it's the controller that overheats and throttles the data transfer rates, not the NAND (the NAND itself actually performs optimally when warm). NAND needs to stay cool enough to retain data but still be warm enough to achieve the requested transfer rates. By the time you reach the temperatures required for the data on the drives to degrade/corrupt the controller would have given out anyway - basically a scenario where the NAND overheats to the point where it becomes the bottleneck is unlikely to happen.
When these drives fail due to sustained excessive heat it's because of the controller dying, not the NAND. Gaming in the context of how the PS5 will use the SSD will be
read intensive, not write intensive so the level of strain on the controller and drive as a whole is nowhere near as high.
None of that's to say cooling is not a concern, it will be, but like I said it's something the PS5 housing itself will need to take care of, so then it comes down to whether the drive is of the correct length or not as long as it doesn't have a permanently installed heatsink.
The Lexar drive you referenced is a prototype. All of the fastest nvme SSD drives you can purchase today come with optional/removable heatsinks since most new motherboards come with their own NVMe heatsinks and a lot of people prefer to use those because they perform well enough, and for aesthetic uniformity.