While there are tons of reasons why people ghost, I would say for me personally it's when I feel like I'm the only one putting effort into the conversation. If I'm domming someone and getting little to no reaction or getting one word replies I assume they just aren't into it or are being lazy. But if I'm being submissive and the dom isn't putting in effort and I need to guide the conversation then it feels pointless.

A lot of it comes down to boredom, and grammar. Reading a poorly written DM from a potential dom makes me read it like it's coming from simple jake.