By manufacturers, you mean receiver making companies, or Dolby/DTS?
Receiver manufacturers use DSPs as they are a simpler solution.
Increasing product cost is a dumb procedure and no one in any sector does that. Nobody said that final end-user price must reflect product cost. Thus increasing product cost of manufacturing only reduces profit margins. Make product as cheap as possible then sell as expensive as the market can tolerate. The trick to high profits. See Nvidia (turing), Intel, Apple.
Codec developers usually provide bulk licenses for manufactured devices, similar to software.
Laptop computer brands: Lenovo, Xiaomi, Huawei, ... all integrate EQ software with the name Dolby Atmos, with the aim of deceiving the consumer sense.
Actually Dolby Atmos is integrated on a laptop that is not decoding software, like on the AV Receiver. It's just an audio editing software, it increases the sound detail. Different with Dolby Atmos integrated in the AV Receiver
In addition, the laptop only supports 2 audio channels only. It also doesn't have all the ports to produce true Dolby Atmos. If want supported, you need uses Dolby Access via HDMI, rather any Dolby mod software mentioned in the forum.
Concluded: Dolby Atmos at this forum is only a simulator, and if it produces 7 audio channels, it is only Dolby Digital Plus, it is not true Dolby Atmos.
But, why do computer manufacturers integrate into their laptops?
Dolby Atmos is a name that has been gaining a lot of attention recently. Just by integrating this name into an EQ software, it certainly attracts laptop buyers
So manufacturers contacted and collaborated with Dolby to create an EQ, which could help them increase costs, when integrating an EQ called Dolby Atmos.
This has happened to HP. They also integrate Beats Audio. But it is only 1 EQ. It is not a set of speakers produced from Beats
Thus, Dolby Atmos on laptops is just a name, to raise the cost of products