Laptop pricing strategies can be difficult to explain even during 'normal hours' - and when you add seasonal events and holidays they can seem completely random. Just keep this in mind:
1. There are all kinds of 'back-room deals' between manufacturers and outlets, like newegg and Amazon. Some times even shipping firms will add special deals. This can produce very attractive listings, but you do well to read the 'fine print', e.g. regarding warranties and shipment: Who offers what, whom to contact for any issues and how cumbersome will the RMA process be, etc…
2. Large manfacturers like Lenovo, HP and Dell are in a better position to offer substantial, across-the-board discounts compared with smaller outfits like Gigabyte and MSI. If you scroll down your linked newegg page, you'll find listings from ASUS, Gigabyte and MSI but they are not nearly as aggressively discounted as the Legion. My guess is that MSI, say, want to sell their laptops just as much as Lenovo, only they can't afford the same kind of financial hit.
3. The arrival of new or updated technology is usually also a harbinger of great deals and killer bargains: The Big Thing right now is, of course, Intel's 8th gen CPUs and everyone is scrambling to clear the inventory to make room for new 8th gen laptops. Just like cars, this means great deals if you're OK with 'last year's model'.
The Legion is down $500 and is now available for $1.300. With specs including a 6GB 1060 card, a 2K IPS panel and a 512GB SSD I'd say it's a killer bargain. It is rather heavy, at 7lbs, and battery life isn't going to impress you or anyone else (users have reported between 30 and 60 minutes of actual gaming).
I would like to make a case for this Gigabyte, also from newegg.
https://www.newegg.com/Product/Product.aspx?Item=N82E16834233193
At $1.630 it is quite a bit more expensive, even with a $70 discount (let's just call it that), but you'll notice that the Legion originally was $100 more. The specs are broadly similar, except you get a 3K IPS panel and an HDMI 2.0 port. That means you can get 4K @ 60Hz on an external monitor, and that's a very rare feature - and one worth considering in my opinion. At 4.17lbs it is almost half the weight of the Legion, and the 94Whr battery promises 'up to 10 hours' - if you can get 5 it's still way more than you'll ever get from the Legion (and most other gaming rigs).
The Legion remains a killer bargain (just bring the power cord wherever you go).
Cheers,
GreyCatz.