A Turian navy modernization program would certainly be a serious cash stream since
even low end calculations put them at
~30 trillion per year just in
procurement and they could likely surge that for a couple years as part of a wartime program. Unfortunately they can't actually get them much. The Turians clearly follow a pattern of 1 Dreadnought, 100 Cruisers, and 1,000 Frigates per fleet. Dreadnoughts take 4 quarter to construct, Cruisers 2 quarters, and Frigates 1 quarter. So each quarter the Turians are paying for 0.25 Dreadnoughts, 25 Cruisers, and 250 Frigates then using the current LLP design and scaling upwards (plus assuming a 1:9 Heavy:Light Cruiser ratio) that comes to a credit total of ~32 trillion
per quarter.
So if we assume that low end was
very low end and that they can dedicate their
entire procurement budget to new PI Ships we are
at best talking one fleet replacement per year. Which sounds well and good until you remember the Turians have
37 Dreadnoughts and thus almost certainly
37 fleets so we're basically talking it taking
two generations to complete the modernization program. Even if the Turians accept that replacing their Dreadnoughts and Heavy Cruisers just isn't in the budget we're still talking an entire
generation of modernization.
Ultimately the problem is that fleets are
expensive and that is normally offset by the slow pace of technology meaning replacements takes decades. Just look at the IRL Nimitz-class which was only replaced (a program scheduled to take roughly twenty years) after forty years of service. Paragon Industries pulling a HMS Dreadnought and obsolescing their entire fleet is going to do terrible things to the Hegemony's economy as they try and modernize.
This isn't something they can really ignore either. In this battle while their Dreadnoughts survived they otherwise lost over
two fleets of ships (>200 Cruisers and >2,000 Frigates) that now need replacing.