I acquired the majority of my pets after I decided to change careers, or I should say semi retire. (no, I'm not THAT old, I just don't need to work full time) Taking care of a large number of animals is pretty time consuming if done properly. I'd estimate it takes me about 3 hours a day at minimum just to feed and clean up aftem them, and when someone's got health issues...possibly the whole day. The amount of time and money you need to devote to your pets definitely increases as the number rises. So, how many pets is ideal for any one person can vary, IMO.
I have 14 cats, 1 dog, 1 donkey, a miniature horse, a llama and four fish. I own my own home on six acres that is mostly forested.
I work occasional weekends at a vet clinic to offset a portion of the veterinary expense, but still manage to run up some astronomical bills. I think my worst month was $800+.
While is does bother me that I don't have hours to devote to each individual cat every day, I do also consider that while I'm their *person*, (well, DH dotes over them too) I'm only a part of their life. I'm not the only thing that gives them love, enjoyment, exercise, etc. For example, the 11 cats who live in what I'll refer to as the cat barn have a social structure where they interact much like any family or community of people. They play, chase each other, groom their best friends, get into disagreements, etc. I'm just part of the picture, although my full attention and laptime is obviously a sought after, important part of their day. From a social standpoint, if I had only one cat that I couldn't devote enough time to I'd probably feel worse about it, if that makes sense...
When I lived in town I had four house cats plus a colony I cared for. My bestfriend, who still lives in town in her own home has three indoor cats, which is her limit.