While the thermal compound does degrade over time, it generally takes around 5 years for the average cheap thermal compound to begin breaking down in a way that reduces thermal efficiency. (but even then, you only get a small increase in temperature, eg on my old dell inspiron 8600, upgrading to arctic silver 5 only lowered the temperatures by around 4C (though since it is regularly cleaned, it never gets very hot, and it is often running at a high load for days on end (currently running my security camera software where the people detection and object filters will max out the CPU)
Many laptops are designed to function at 100% CPU, GPU, memory, and hard drive load at 32f - 105f continuously.
As with vacuuming a laptop, it is generally the only way to get the dust out without opening it and doing a full cleaning (compressed air generally loosens it and most of it will remain in the heatsink and fan area.
Furthermore, it takes a lot more air movement than what is on the standard vacuum cleaner to generate an unsafe amount of static, and due to the fan design, the air pressure will not cause the fan to spin.
(I have been cleaning my inspiron 8600 this way every 4-5 months or so for about 7.5 years now and it has been running most of the time doing various things, and still works fine. (I also clean my other laptops this way)
Many people get cooling pads when their system does weird things like throttling in the summer or randomly shutting down. (In every single case when a customer has come to me with a laptop repair and they also had a cooling pad, when cleaning the laptop, I would find that the heatsink in every single case, was almost completely clogged with dust, and a quick cleaning would lead too a 20+c drop in temperatures.
And while laptop cooling pads exist for a reason, the problem is often the reason. Most laptop owners have never taken the laptop apart to clean it, an din most cases, even attempt to clean the heatsink. And for those users, a cooling pad can often help keep the unit running for a while longer before the heatsink is completely clogged (or at least extend it's reliable function to be long enough to meat their next planned laptop purchase)
While there are rare cases where a laptop may overheat with it's stock cooling with no dust, that is extremely rare and is generally only present on first gen laptops that try to push how thin laptop can be made (eg some of the more modern macbook pro laptops would begin to throttle at full load if the room temperature is at 75-80F, and at the time it was caused by inadequate cooling, they were using high end CPU's and tiny heatsinks and thinner cases than any other laptop maker at the time was using for similarly spec systems.
but other than a few rare exceptions, almost all laptops are designed to meed a standard range of 32-105F at full load (ambient temperature of 0-40C)