@decodx provided a detailed reply explaining some links between them. Check the below links.

https://bt.irlbtc.com/view/5465425.0
https://bt.irlbtc.com/view/5384944.0

These are just a couple of links proving their connection and there are many more out there. It's like some sort of huge mafia organisation with its headquarters most probably in Russia.

Like it or not, we can never come to a time when every person in the world will automatically know what to do when they want to choose an online casino to play on, many people and fond of not learning from other people's mistakes but only learn from their very own mistakes. For people like this, they will always fall victim to one scam or the other before they learn the proper way to search or look for something before engaging in that thing, so as they don't fall victim again.

It's no longer a new thing that most of the victims who are scammed by 1xbit always come to this forum as newbies, and their issue with the site is usually what brings them here, this tells us that, some people only begin or start researching a service only when they have been scammed, and this is what leads many people into falling for the 1xbit tricks..

scammers will keep scamming until not being busted ,authority must turn against this scammers , 
hope that some day they will be going to face everything they took from gamblers , it is not easy to earn and
just be scammed when gamblers seeking to refuge their money and make at least some amount earning from
their capitals.

The problem is that obviously there is no such authority which could effectively prosecute scammers from other countries and even if someone tried to locate and find those scammers, the amount of money stolen from the person must be pretty much huge for someone to go through a big investigation and prosecution process. It would not make sense, for example, to spend up to several thousand dollars to try to locate and find a scammer, if the quantity to be recovered is less than that.
Even if there was a centralized and effective authority which could punish scammers somehow, the number of them is so high and so many scams happen so often, that this organization would need to be funded by several governments at the same time, in order to bring justice to hundred of thousands of victims worldwide... Sadly, there are countries where scammers will continue to feel secure from prosecution in the long term.

Ask yourself this question, 

How easy it is to follow another person's mistakes, and try to learn from them?

The answer is almost none,  why I pointed that out is because many times we read and hear many other people's stories and experiences and are unable to follow the lessons,  this is why it is better to experience things yourself to learn the best lesson and that way your experience will fit into your personal environment,  this is why we need to learn to take the time to seek for help and also try to experience things ourselves.

Most of the victims of 1xbits are mostly newbies and those who don't have any information about the notorious scamming and will only learn about it when they have already become victims of the scams.

So we do already have that thread in speaking about relation among the two.

There is no significant difference. Both sites are operated by the same company, 1xCorp N.V., or something like that.
The only differences are in the frontend design and the fact that 1xbit does not have a license, so it operates illegally.
Link Source

and this one too
https://bt.irlbtc.com/view/5412793.20

There are definitely alot like you said, but for me personally, I have gambled On 1xbet on several occasions, I mostly played sports betting on that casinos for several months, and needless say that, I never had any issues, both in terms of them crediting my winnings and me withdrawing them, never had any issue, and one other good thing I will also have say about 1xbit is that, they sure have a sports book with one the best odds, and one feature I like in that casino which I unfortunately have not found on any casino (even on my favorite casino, which is stake) is the ability to still win a multi bet ticket even when one or two games from the ticket fail to meet up as predicted, 1xbet have a system that minuses those failed bets in the multi-bet ticket and only pays the gambler for the games that was predicted correctly, only that they pay at an odd that is lower than what it initially was - this feature I've found to be really helpful for gamblers since it has helped me win some of my multi-bet tickets which should i ordinarily should have lost because not all the games in the ticket played as I predicted.

So, that is it for the good side of 1xbet, now coming back to scam accusation against them, I would first say that, there is actually no online gambling casino without unsatisfied customers, and personally, I've always thought or assumed the majority of scam accusations against 1xbet is possibly due to their connections with 1xbit, which is a well known scam casino themself.

1xbit doesnt even has a license... valid or invalid... so everything is said.

I think that depends on the license provider. Although reputation is very important but gamblers nowadays are aware how important a license is. I like to ask you a question? Do you know a casino that is popular in the forum ^{( so we can check)} that has a good reputation but doesn't owned a license? If you can tell me one, then I might change my perception about license + reputation which IMO are both important.