Since Lemmy instance are not backed by commercial interest, but rather by nice volunteers and donors that have money and time to spare, they will be heavily affected by economic downturns (we still can see commercial interests still affect users negatively tho with reddit). Here are my thoughts on the matter:

• as far as I understand the owner of the domain: https://lemmy.world even has to pay for this fancy domain name in the DNS system ... every month subscription service style
  • (and tbh I hate the Domain name system) why should I fund it with my own money?
  • if you hosted with an onion site over tor that expenditure would not exist, but how would users discover your site then? Let me know if you know something about this
• in times of deflation (meaning money becomes worth more, spending some money on a self hosted lemmy instance becomes nonsensical)
• tbh if I hosted a lemmy instance and the users of my instance posted high quality content in quantity I would use it to train my own LLM, that would at least create some economic incentive for me to host such a page ... but managing spam and bots will be HARD

That is why you should always back up your comments on your personal device, would be nice if lemmy had an automated way of doing this (I should look into this more)