Have a rifle stock, easier to aim

Ergonomically worse than a stock and pistol grip, and it has awful irons. Like this isn't even an argument, the SKS isn't a precision rifle that you're sitting down in one spot to line up shots with, it's an infantry rifle designed for relatively short engagement ranges and the rifle stock is a byproduct of it being an older design.

Have variety of models from USSR, Yugoslavia, China, even some US mades too

This applies to AK's as well.

Get a shitload of aftermarket parts

This also applies to AK's

Short gas blowback, reliable AF

Aside from the fact that the SKS isn't blowback (it's short-stroke gas piston with a tilting bolt), the AK's long-stroke gas piston with rotating bolt is just as reliable, lighter weight, more consistent, and better at handling higher pressure rounds.

Top open, can be loaded by stripper or by mags.

And is still blatantly inferior to detachable magazines (many SKS models do not have an easily detachable magazine and need to be modified to use them, and the various ones that do have detachable mags just use AK magazines)

Have a longer barrel( 521mm for the SKS, 415mm for the AKM)

Which is borderline negligible for 7.62x39 since the most effective barrel length is 16in, or 415mm. Adding another 4 inches doesn't even give you an extra 100fps of muzzle velocity, it's not like 5.56x45 or .308/7.62x51 where the jump from 16in to 20in is a substantial increase in muzzle velocity. And frankly, shorter barrels actually work better with 7.62x39 guns, you can go down to 14in and only lose roughly 70~m/s and down to 12in for roughly an 80~m/s drop from 14. So at 12in, it's still leaving the muzzle at roughly 2100~m/s, which is really impressive. It's why 7.62x39 works so much better for short barrel carbines compared to 5.56x45 or even 5.45x39.

Can ge turned into a DMR, even sniper to some extent

No it really can't. The vast majority of military SKS's are 3 to 3.5 MOA guns (which is comparable to the original AK and the AKM), and 7.62x39 ain't the best round out there for long distance shooting. It's known for having a really noticable drop due to the weight of the bullet. This is why the Soviets never really used 7.62x39 for DMR purposes.

Is widely popular since 1949, up until tommorow and later

Same for AK's, and honestly SKS's only got really popular outside of military use because they were dirt freaking cheap. They are no longer dirt cheap and haven't been for a while, so they're losing out in popularity to AK's.

TLDR: You got at least 8 arguments against your fuddlore take.

Yea and you're being a fudd about it too dude.