Quick calc, "initial draft" tech alchemy is 10 Plat Tech = 100 cobalt + (100-95=)5 platinum + 1h of fuel for 3000+tf (which would be 20 fuel blocs or around 350k ISK).
So that's 1 PT = 10 cobalt + 0.5 plat + 35k ISK for fuel (the old alchemy 20:1 tech:cobalt replacement ratios)
Plat Tech used to sell for around 92k ISK lately, but it will almost certainly be falling.

Cobalt used to sell for ~500 but it recently spiked to over 3k, Platinum was around 2.5k and now it's around 4.5k, so that's 30k from Cobalt, barely over 2k from Platinum, 35k from fuel, making PT cost 67k to manufacture.
Add in at least 100m ISK/mo per reactor profit to make it start worth bothering with (7,200 units/reactor/month), so another 14k minimum, and you're looking at a 81k price for PT down from the previous 92k trade level.
Not a lot less, but still noteworthy.
That would cap tech price at around 145k-155k or thereabouts. Assuming Cobalt/Platinum or fuel block prices would not spike, and assuming people would be willing to accept a mere 100m per month from a reactor. So, maybe, tech price won't be going down much in the long run, but it won't go up more as it could have if there was no tech alchemy at all.
Depends how long they'd keep the reactions at that level.

And of course, they could bring the replacement ratios further down from 10 Cobalt and 20 fuel blocks more in line with other current alchemy numbers (2.5 Cobalt and 5 fuel blocs and just 3.5k minimum added expected minimum profit, so the new 5:1 alchemy), which would make it much cheaper (assuming cobalt and platinum would NOT spike even further in price, to a mere 22k per unit of PT). That would cap tech to a negligible price compared to the current level, probably below 40k per unit.
Of course, in that case, I expect both cobalt and platinum to go up more, and I also expect people to want more monthly profit from reactors than a measly 100m/mo/reactor, so before any further changes, we might as well still see tech over 60k per unit (or even a bit higher) even with the VASTLY buffed alchemy reactions.
Depends how much it takes them to implement OTHER changes on top of just alchemy.