Roman helmets: Imperial Gallic/Italic and Ridge - comparisons and sources

[CaesarAugustus]

Following the third century crisis, the society was not any more able to support some quality products. The answer from the imperial infrastructure has been to renounce to this quality.

Utter rubbish. Fourth century equipment and metallurgy was the best the Romans ever had.

The simple components of the ridge helmets could be made by relatively unskilled and inexperienced smiths. The downright crudeness of a number of examples suggests that they often were. Even the finest pieces hardly match up to second century standards of construction.

Not only, then, was there a complete change in the design of Roman helmets. There was a simultaneous decline in standards of manufacture. These changes must be seen against the historical background of contemporary developments in the army and the armaments industry itself.
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The collapse of the coinage from the middle of the third century would have paralysed this system of supply. The army could not afford to buy the weapons, while the armourers could not sell their wares nor buy raw materials. The operating system of the industry, which had endured for several centuries, collapsed.
The development of a crisis in arms procurement is, in my opinion, the direct cause of the establishment of the state arms factories, or fabricae, which start to appear under the Tetrarchy. It is suggested that from the 260s the state was forced to bypass the
financial crisis and started to maintain the armourers directly, by providing rations and security in return for product, leading to the gradual absorption of the armourers into the Imperial service. This process reached its logical conclusion when Diocletian put it on a regular basis and built new factories to accommodate (and control) them at strategic points across the Empire. It seems that the state wanted quantity production, not fancy quality, hardly surprising when faced with the task of supplying an expanding army suffering high rates of attrition, as Diocletian's surely was. 

This is coming from a professor that is still in activity, has studied the excavations of dura europos from which is coming our knowledge about the ridge helmet, and has a resume that you can easily find on internet. This largely defines your sentences free and, as seen so far, incorrect.