Not likely to be a lockdown, but it is a lock-in. It lets you buy stuff that you can only run on OS X, without ever giving you another option. Similarly App store is a lock-in to iOS, as well as a lockdown.
Can't say I like it... 10.6 might be my last version running OS X, what with Apple growing more and more authorative, and linux getting better and better. Can't say I much like the GPL either though, I prefer the BSD license on my own stuff.
One might hope, that when people realise that they can't run their programs if they switch from OS X, there'll be more incentive for a wine-like program. GNUstep already aims for source code compatibility (that project is actually older than OS X itself), and IIRC NetBSD has support for the Mach-O binaries, so some of the work is already done.