I would hope we're not talking about three-point increments here. Obviously I'm not going to forgo a good roll just for three points, and I sincerely hope you are not infusing gear with cores for three points at a time, for the same reasons you listed above. If people actually are doing that, I'm not surprised they are short on cores. The last time I infused something for cores was when I added over 30 points to my Raiden Flux. Most legendaries drop frequently enough that you can do the glimmer-only infusion for those smaller upgrades. Exotics are the only real concern in that regard and it seems obvious to me that you should be waiting for substantial upgrades before spending cores on that.