Well, I'd really like to be surprised ... but I don't expect the law to "sunset" without it being renewed.
Also, I live in CA, and I don't expect our state to wake up one day, even if the national law sunsets, and decide to change our laws to allow the purchase of high capacity feeding devices again ...
I'd like to be wrong, but I won't hold my breath ...
I also went out and legally purchased some increasingly expensive (supply & demand economics) magazines before the state law took effect, just like I bought a Colt Match Target rifle before the state law took effect here ... and yes, I properly registered it with the state as required by the law.
I'll say one thing about some "pre-ban" magazines, though, and that is that a crap magazine is still a crap magazine, regardless of how many rounds it may legally accept. I've always avoided the purchase of magazines which appeared to offer anything other than perfectly reliable functioning in my firearms, although I made an exception for some magazines I was buying in the months before the local laws took effect. Fortunately, I had a chance to test fire many of them and learned the error of my ways, and had sufficient time to return them and get a refund.
Nowadays, I'd worry more about whether or not my magazines were high quality and 100% functional ... and LEGAL ... than how many less rounds they accepted than "pre-ban" or "L/E" magazines. There are just too many pre-ban, after-market magazines that are "less than optimally reliable", you know?
And you know, what always seems to be "forgotten" is that misses are still misses, and since you just can't miss fast enough to "win" a deadly force encounter, I'm still far more concerned about MY skills and accuracy than I am about the number of rounds in my magazines. I get to see a lot of folks qualify with high capacity magazines in my job, and for a lot of them, having more rounds in their magazines only gives them the opportunity to miss more ...
It's always been a funny thing, but it's not uncommon to see the older, veteran cops who started their careers using 6-shot revolvers, and who still complain about the new-fangled semiauto pistols ... who often shoot more accurately, and miss less often, than the younger wunderkind who consider revolvers as something used by "has-been", antiquated cops ... I guess only having 6 rounds available may have had some small influence on the older cop's consideration of accuracy and aiming, maybe? It certainly did with me ...
If I decide to retire out of state ... and I'm seeing more and more cops leave California when they retire ... then I'll probably take the opportunity to legally buy some additional pre-ban magazines for my rifles and one of my semiauto pistols, and maybe a couple of pistols that use the older, pre-ban magazines, as well ...
But I sure wouldn't spend an arm & a leg to legally buy a pre-ban magazine at several times its original cost. That's just ridiculous. Especially when we're only talking about a grand total increase in capacity of only 1-5 rounds, for the most part ...
I mean, I used to feel comfortably armed carrying a M66, and later a M686, first with a couple of 6-round dump pouches, and then with 2 speedloaders, on my duty belt ... and if I worked one of the more "active" or even more rural, beats ... with another couple of speedloaders or speedstrips in my jacket pocket. Somehow, I managed to survive all those times when I was carrying a grand total of only 18-30 rounds on my person ... not to mention a standard Remington 870 with a 4-round magazine.