Valve employs an army of economists (notably Yanis Varoufakis as alumn) to make these decisions. It was certainly purposeful and will balance itself out.
It's not so much a depreciation of knife textures, as a distribution of this value down the chain of item rarities.
Valve, as a digital feudalist, generates funds, practically for free, from both transactions of items and the lootboxes. It operates the markets on which digital goods are traded, taxes all sales occurring on these platforms.
After they already went and built the torment nexus (and were paid handsomely for it)
I wont google him, but take at your word an assurance that he can be trusted with the highest levels of economic decision making.