With the exception of the above sentence, it's all pretty much on the money.
I have, and still do (mostly) service myself. If the service car needs to be moved, there's always helpful people on hand. However, in this day and age, central service is generally the go. Service is usually at the start finish, so your service point doesn't need to move. Yes mates are helpful, but not essential.
Chequebook: Rallying is as expensive as you want to make it.
Alternatively, it's as expensive in preportion to how fast you want to go.
My two Corolla's ate 2 tyres in about 120km competitive. Chewed fuel at about 1 litre per 3 kms. Regular box, suspension, diff rebuilds, etc.
Conversely, my Excel series car ran for a year on 6 tyres and about $20 in fuel, and you never had to touch it. At all.
Panel beater: If you're any good, you wont need one.
Engine builder, agree these can be handy, but not essential, particularly if you're running something late model and can just buy import donks.
Rallying can easily be done on a budget.
Join a club. Buy a car. Have a go. :)