It looks like 2048 is a registered trademark of Ketchapp (obviously not the original author of 2048): https://trademarks.justia.com/865/87/2048-86587551.html . How applicable is this trademark and why are there still dozens of clones of 2048 on both Apple/Google Play store?
In the US, a trademark is a word, phrase, symbol, design, or combination thereof that helps consumers identify a particular product.
If you register a trademark, you have legal grounds to prevent others from unpermitted use of your trademark with their product. For instance, Nintendo has trademarked Super Mario Bros. If someone attempted to market a game using that trademark, Nintendo would be in a strong position to litigate.
However, Nintendo's Super Mario Bros. trademark does not prevent other from making platformer video games with powerups, modifiable terrain, princess rescuing plots and so forth.
As such, trademark is only relevant to clones if:
- The original game has a trademark AND
- The clone is attempting to make use the trademark (I.E. use it as part of their branding) without permission.
As the question of whether or not Ketchapp can 'apply' their trademark, it depends on the context. It would appear they haven't successfully maintained control of 2048 as a trademark. Furthermore, it appears that 2048 is now used to describe a general category of game. Such generalization sometimes dilutes a trademark.
That being said, the Google Play Store is not exactly the same as a courtroom. Presently, here's what the Google Play Developer Policy Center states about trademark:
We don’t allow apps that infringe on others’ trademarks. A trademark is a word, symbol, or combination that identifies the source of a good or service. Once acquired, a trademark gives the owner exclusive rights to the trademark usage with respect to certain goods or services.
Trademark infringement is improper or unauthorized use of an identical or similar trademark in a way that is likely to cause confusion as to the source of that product. If your app uses another party’s trademarks in a way that is likely to cause confusion, your app may be suspended.
Initially, results would depend on whether or not Google agreed with Ketchapp's claims. Results beyond that might further depend on any legal developments in court (Google doesn't agree, so Ketchapp files a motion, Google does agree & some other dev files a motion when their app gets removed, etc). Further speculation is likely to be better suited to the Law Stack Exchange or actual legal council.