Some products simply exist to make others seem more attractive.
Like in grocery stores the luxury brand is never profitable alone. What makes it profitable is that instead of buying the budget brand people then choose the standard brand. Without luxury brand, most go for the budget version.
So how do you push people to adapt RTX? Make it look better than it is.
That's true to a certain extent, but I don't think it works quite as good in this particular case.
If this were like the iPhone where Apple sells different tiers, I'd agree with this since the entry tier is just their to feel inferior enough to up-sell you to buy the model with more memory which costs you and extra $100 or more, but maybe only a tenth of that for Apple.
However, in this case the 1660 Ti is using a different die which means that they want to be able to sell this part at some point. Apple can just offer a bad value entry model that it doesn't have to sell since the rest of the phone is the same and can easily be sold with more flash memory.
NVidia can't turn a 1660 Ti that's priced to make people want to buy an RTX card instead into that card. Given that volume increases as you move down in cost, NVidia will want to make a lot of these because if you look at history, the $150 - $300 market segments sell a lot more than everything above that. If they make it too unattractive, they risk another glut of cards and having to halt production.
$300 could work if the 2060 were trending well above MSRP, but it appears that there's no problem getting one at that price. Sure there are some AIB offerings that are higher at $380 (or even some above $400) and that creates space for a $300 card, but I'm not sure how much NVidia wants to drive people towards the 2060.
Unlike Pascal where the 1060 was a full die GP106, the 2060 is actually the salvage part (cut down 2070) so unless yields aren't as good as expected and NVidia has a nice natural supply of chips that can't work as a 2070, pushing customers towards the 2060 just means that NVidia would need to artificially disable dies that could have been sold as a 2070 to increase the supply of 2060 parts, unless they're fine with prices increasing above MSRP.
Or you can knock $20 off the 1660s and that works too, but I just think NVidia will go for a cash grab on release, with lots of room for future price cuts.
That's certainly a possibility, but if it were me I'd rather have an almost guaranteed sale now at $280 instead of risking make people wait, potentially long enough for AMD to have an actual product that can compete above $250.
We don't know what Navi will be like, and it's a little hard to get on the GPU hype train for AMD after the last few years so I wouldn't assign a high degree of probability to AMD having a knockout product, but any competition is going to force NVidia to move more on pricing than the current lack of it that they're facing right now.