I wonder what happened to OO databases?

I remember in the 1990s a plethora of databases were springing up that claimed to be object-oriented. The truth is however other than attend some vendor presentations and demos, I have hardly ever encountered actual use of any of these products.

From wikipedia, object database management systems grew out of research during the early to mid-1970s into having intrinsic database management support for graph-structured objects. The term "object-oriented database system" first appeared around 1985. Notable research projects included Encore-Ob/Server (Brown University), EXODUS (University of Wisconsin), IRIS (Hewlett-Packard), ODE (Bell Labs), ORION (Microelectronics and Computer Technology Corporation or MCC), Vodak (GMD-IPSI), and Zeitgeist (Texas Instruments). The ORION project had more published papers than any of the other efforts. Won Kim of MCC compiled the best of those papers in a book published by The MIT Press. Early commercial products included GemStone (Servio Logic, name changed to GemStone Systems), Gbase (Graphael), and Vbase (Ontologic). The early to mid-1990s saw additional commercial products enter the market. These included ITASCA (Itasca Systems), Jasmine (Fujitsu, marketed by Computer Associates), Matisse (Matisse Software), Objectivity/DB (Objectivity, Inc.), ObjectStore (Progress Software, acquired from eXcelon which was originally Object Design), ONTOS (Ontos, Inc., name changed from Ontologic), O2[2] (O2 Technology, merged with several companies, acquired by Informix, which was in turn acquired by IBM), POET (now FastObjects from Versant which acquired Poet Systems), and Versant Object Database (Versant Corporation). Some of these products remain on the market and have been joined by new products (see the product listings below). Object database management systems added the concept of persistence to object programming languages. The early commercial products were integrated with various languages, such as GemStone with Smalltalk. For much of the 1990s, C++ dominated the commercial object database management market. Vendors added Java in the late 1990s and more recently, C#.

Also according to wikipedia, as of 2004, object databases have seen a second growth period when open source object databases emerged that were widely affordable and easy to use, because they are entirely written in OOP languages like Java or C#, such as db4o (db4objects) and Perst (McObject). Recently another open source object database Magma has been in development. Magma is written in Squeak. (I haven't ran across any of these, however...and until reading this from wikipedia had never even heard of last three products...)

So my question today, is if this is a market that will FINALLY take off...