The answer to your question depends on what percent back you think is "holding it's value". There are very few brands of bags where you will get most or all your retail price back if you sell it in the future.
It's been my experience that more well known or "staple" bags keep their value better because over time people will still recognize those bags as part of that brand and want them, where if you have a bag that may be discontinued, it will be harder to find a buyer and thus even in a consignment buyout you will not get as high a percentage bag. However, with LV's, if i even get 60-70% back of my retail price, I found that good.
Bags, in general, are meant to be luxury goods that are enjoyed and used and not investment commodities. The one exception I can think of is Chanel flaps, with their self imposed scarcity as well as constant very steep price increases, that if you bought a classic flap and held it in mint condition, you could possibly get what you paid for it back since the retail price may have gone up remarkably since then making what you paid a good deal. However, that's only getting your money back and you would have to wait a very long time to make any profit, which makes it an unreliable investment.
Long story short, I think real estate is a better investment, by far.