I'm not sure it's key to mutual aid that people are similar demographically, I'd say the key point of it is to share resources unconditionally. A traditional charity does not give unconditionally, as they gate-keep who is or isn't 'deserving' enough of help (that's not to say that traditional charities can't do great work of course). Mutual aid also recognises that different people's needs might be different: one person might need financial assistance to avoid eviction, another might need a second-hand mobility aid, and another might need a hot meal brought over a few times a week. So the aid is mutual, because the same people might be recipients of some types of aid and givers of others, if that makes sense.

Thanks for your reply! I'm definitely noticing this in all the mutual aid spaces I'm involved in, and what concerns me the most is that most followers are very young (18-24 years old)! Obviously, these are not the kind of people that are able to commit to for example donating $100 to someone in need on a monthly basis. What I'm not sure about is whether this is because the networks I'm involved in are mostly based on Instagram, or whether it's a trend in mutual aid networks in general. Social media is ideally positioned to connect wealthy folks with those in need, though, and it doesn't seem to me that many wealthy white suburbanites are going out of their way to establish mutual aid networks offline locally. If somebody knows of a specific example of a mutual aid network in which wealthy white donors are predominantly active, though, I'd be super interested to hear about it!