S. R. Faruqi:

In this verse there is, for the observer, a dazzling devastation [hosh-rubaa saffaakii]. The relics and buildings of kings and lords, or of their feats, remain behind. But the age is so stony-hearted or unfeeling that it erases the signs of their graves, or their tombs turn to dust, or their bodies themselves turn to dust, and then that dust is used in making houses.

The people who make houses in this way-- how unfeeling and heedless of instruction they are, in that they don't reflect that when their houses are being made from the dust of the bodies of kings, the fate of the house-makers themselves won't be any better than this.

Instructiveness, and the constant changing of the times-- these are obvious ideas. Expressing them by means of an entirely everyday perspective, he has created an uncommon tension. Man dies and becomes dust, and from dust houses are built-- through the bringing together of these two everyday insights, power has been created in the verse. Individually, they had nothing special about them.

And having said in the second line that those very people whose dust is being made into houses, have left their traces/relics behind them when they went-- in addition to instructiveness, he has also created an aspect of sarcasm: that the houses that are being built from their dust are themselves too a kind of trace/relic.

A theme similar to this, he has expressed at two places in the first divan [{208,2}]:

safar hastii kaa mat kar sarsarii juu;N baadaa-e rah-rau
yih sab ;xaak aadmii the har qadam par ;Tuk ta))aamul kar

[don't make the journey of life casually, like a road-traveling wind
all this dust was humans; at every footstep, just pause a moment]

Also in the first divan [{215,8}]:

dekho nah chashm-e kam se ma((muurah-e jahaa;N ko
bantaa hai ek ghar yaa;N so .suurate;N biga;R kar

[don't look with a belittling eye on the settlement of the world
a single house is built here-- after faces have been destroyed]

But these don't have the clarity of perspective that has made the present verse so uncommon.

FWP:

SETS
MOTIFS == HOME
NAMES
TERMS

The first thing this verse made me think of was the many old, derelict tombs and pavilions all over India in which people now live. To have people living in their tomb, or tearing down their tomb for bricks to make a house, might almost seem like part of the price that 'great men' pay for fame. It might not necessarily be a sign of the hard-heartedness or decadence of the living. The two other verses that SRF cites both envision the reuse of the dust of former generations as a universal, inescapable part of the human condition.

More intriguingly, the emphasis could instead be made to fall on the contrast between the present state of the great ones' dust (which is so dead that it's unknowingly-- and inevitably-- used for brick-making) and that of their aa;saar , their traces or signs, 'effects' or 'impressions', which perhaps include reputation or memory (see the definition above). These aa;saar still are, as the second line tells us, very much present and apparent on earth. So if their bodies are gone but their traces or effects remain, is that a form of death, or of survival?

Or, Sufistically speaking, perhaps 'to make a house/home from the dust' of some great man could even be an extreme form of 'taking refuge in' him. Perhaps it's a tribute that wouldn't be extended to someone whose memory was no longer alive.