The Old Testament's picture of the political situation before David is a bit more complex than the brief mention made in the News Focus article "Judging Jerusalem." Two kingdoms were not well-established before him. The Old Testament records a fairly loose association of northern and southern tribes under "judges," with power then consolidated under a single king, Saul. After Saul's death, there was a brief division into northern (weak) and southern (small) kingdoms before David became king over the entire region; however, the north was restive even under David and more so under Solomon.
Apart from David's palace, which could have been seized from the Jebusites rather than built new, there is no explicit mention of building being done under David. As a new capitol, formerly the isolated fortress of an enemy minority, there probably would have been rapid construction in what had been relatively deserted areas.
To reliably interpret the archaeological record, archaeologists must seek to examine the evidence, regardless of whether it supports a particular viewpoint. Trying to prove or to undermine the Bible equally violates this principle. Since the Bible is genuinely an ancient document from the region, it does provide useful information for the archaeologist, whether or not it is fully accurate. On the other hand, its intent is theological, rather than as a guide to archaeology. Also, the Israelite perspective must be remembered. An amazing metropolis to the eye of one used to small villages might be small in comparison with the great cities of distant empires.