well that is the problem. Yes, Federation has the automaton technology, replicator, etc. In peace time, they are abundant. But in a war, with massive planetary bombardment, convoy interception, etc, such luxury will be vanished. A dominion massive planetary bombardment could decrease the 24th century colony into stone age. And if that happen, how do you operate the "only god know how to create" Replicator Technology.
Even an idiot know that power supply, planetary infrastructures, freighter convoys, resource storage, etc are the first priority target in battle. And let we see the fact, that in 20th century only, a city bombardment could destroy everything. So how could the Dominion fleet with 24th century technology couldn't reduce a colony into stone age? And with the planetary power supply being bombarded by Dominion, how could repilicators work?
And let see the fact. Federation were lost. Dominion Force move deeply into their territory. Even it doesn't reach Earth, Vulcan, and Andoria, it's reach Betazed (if it's canonical). So we can assume that at least 1/3 of Federation territory has become the battlefield.
Say replicator can create anything just with Dilithium crystals (although I think that it is bullshit). But even with only Dilithium Crystal as the resource, they still need mines to extract the resource. And what happen if those mines got bombed by Dominion Forces?
And about 150 worlds..., we all know about supply and demand rules. What happen if 1/3 of those worlds being bombarded, hundreds of dilithium crystal mines being razed, millions of power supply and hundreds of freighters being destroyed? It will disturb the balance. The supplies won't be able to meet the demand, and the economy of the Federation of Planets will be disturbed if not crippled. And to say being "Disturbed" is already being very optimistic, because mostly it would cripple them good.
Well... unless Dominion are more than idiot, or Dominion War is actually ships shooting the other ships, and doesn't involve planetary assault at all.