Cloning toppers in the industry is not something invented by crypto gambling sites. Just look at the several examples that Google is giving us:
Not all those that copy others are dying out, as you can see from the list above. If you are honest with your customers and the functionality of your site is on the high level, you have every chance of being successful, but being at least slightly different wouldn't hurt, of course.
Apart from gambling industry, even in other industries where there is competition and where there is growth, there is a level of copying that is seen. I am an advocate that nothing is totally new, every idea must have emanated from other ideas and then refined to something new. This is understandable to a large extent and not to copy the whole idea or design of another company. If you copy more than acceptable, you the copier will lose your own originality. There will be no uniqueness attached to your brand. Companies that depends much on copying others doesn't last in any industry because they are not unique or lack brand.
Some companies who copied and became successful, you will notice that at some point they will tend to rebrand when they have gotten the required customer base to compete favourably in the market.
Gamblers sometimes doesn't care, they only care if all the games can be found readily and easily and withdrawal not giving issues they will make gamble and go their ways. So, it is the clear duty of gambling sites to patent their design and other related unique things, so that they would be legally eligible to take actions against obvious copy cats.