I tend to keep purple items that are useful (obvious ones) in storage in case I ever decide to switch to another build or just need a new item to fill a gap when I upgrade something else. You know, that sort of thing. I don’t tend to delete them if I may find them useful one day.
You can imagine this means I now have some items I may potentially get to roll up to legendary. Awesome! Exciting times 
I just checked how many I have stored in the lifetime of my FSS character (several months of playing almost every day since launch) and it’s… maybe 20 items? I’ve sold or destroyed maybe three times that tops from the proc gen items I’ve gotten from mutations that I don’t think I’ll ever find useful (and I really mostly get the good stuff from there as I don’t run elite zergs every day so appreciate some other players will generate more than I do). But bear in mind that the vast majority of proc gen purple items I get (which are the minority, you tend to get more green and blue ones) are utter trash and represent the massive majority that I simply salvage on the spot.
I’m sure the market isn’t quaking in its boots at the prospect that I might roll maybe one BIS item in all of those 20 items I have (if I can even roll them to legendary, I’m not sure how I got them all).
And if it means that more 2 perk items sold on the market may now be bought as a prospective legendary item… Surely that will only be beneficial to the economy???
I get the impression most people arguing against this have it in their heads that all the purple items you see can get rolled up but the vast majority of items from mutations are fixed perks and the only way you’ll get the random 3rd perk on those is if you get them at 600gs on pickup. They’re not proc gen. The number of purple proc gen items you get from an M10 is maybe 4 or 5 and they’re almost always trash by RNG.
It’s so frustrating when positive stuff gets this sort of roadblock from wannabe expert economists who are concerned about their market value. Players will still need 2 perkers for the same things they need them for now. The chances of actually getting BIS on even a perfect 2 perker is still very low. You’ll still need scarabs to guarantee a 2 perker you need, with a chance of rolling it up (and I think that it should be possible for the person crafting the item to optionally roll it up to legendary when they craft it, using a set cost of shards - that’s a lot higher than standard, like several thousand - at the point of crafting, that binds the item to them - like a personal guaranteed legendary item every time but only for them).
The only issue I’m concerned about here is item marcation between those which can be rolled up and those which cannot. This is so important! If you look at any purple item, it’s so difficult to know if it qualifies for the 3rd perk at 600, even now. But with these changes it’ll become impossible for the average player to understand this. Or even know that it can be done at all! I had no clue you could roll up OPR weapons until this week, for example! Nothing in the game tells you this!
That needs to change so that when I’m looking at an item, be it one I found or one that’s being sold, that I know its true potential value. This is even more important because the value of these items will increase with the patch and if I can’t tell which can or cannot roll a 3rd perk then I’m going to waste a ton of gold and shards finding out the hard way.