We’re talking about multiple industries here. In streaming Netflix is dominant. In terms of movie production studio Netflix is the also-ran compared to Warner and Paramount.
A purchase by Netflix would give them something they currently do not have. A purchase by Paramount is a much more direct merge of two competitors.
If the industry is defined as one that makes entertainment, then no one is dominant. Oracle and bytedance (tiktok), Meta (instagram), Alphabet (youtube), Reddit, Video Games, and even the sports leagues are huge competitors for screen time.
Even restricting the industry to professionally made videos, there is Apple, Amazon, Comcast, Disney, Netflix, Sony, and Paramount. Ignoring the small ones like A24 and Lionsgate. Having or not having Warner Bros be a separate entity seems inconsequential, considering the weight of the others.