Yeah, $2000 sounds like a lot. That is until I look at how we'll blow $2000 in a weekend and not even remember what we got or where it went.
I'd support going with another machine you have laying around (if you have one). Or, buying something cheaper or used if you need to for budget.
But, whatever it is, $2000 isn't a lot to throw at a kid for something that will serve them a while.
MacBook Air may not be the ideal machine. But, whatever you want, whatever you're comfortable with. Whatever you want to do.
I can support giving a kid a computer pretty easily. Even at a young age. I've seen what it has done for my kid.
She's not a nerd or anything. Just using it for activities that are fun but also educational. She feels like she's playing a game. But, she's actually learning reading and math. They're essentially structured fun games.
Good enough that I'd play with them. But, educational in every aspect.
It's not like she's being forced to learn computers and start programming or something. The computer is merely a device. She's learning the educational material while she plays, not how to compile a unix program or something like that.
Spoiling can be done with no money at all. I could spoil a kid without spending a dime. Doesn't matter what you spend on them. Money is not a concept that is of any importance to a young child.
What matters to them, is what they see, how they are treated, what you teach them, and how they are taught to behave (among other things).
Giving them an educational tool, is not spoiling them. Letting them do nothing, would spoil them. I'd rather she be going between her dolls and the educational toys, than to have her camped out on the couch doing nothing. She's got activities outside the house, she's got typical girl interests, some tomboy type interests (like cars and such), and a healthy interest in learning about the world and the things in it.
It's not the things that spoil them. You can spoil them and still never give them a single possession.