No, there are no patents at all, anyone is free to use any crypto at any time. Despite that 70% of the value of crypto is in bitcoin, 62% more than the next most valued crypto.
The reason bitcoin is comparatively highly valued is because
- it has the longest chain
That means that all the hackers who want to maliciously destroy bitcoin or use an exploit to create more for themselves are focused on bitcoin. There has only ever been one hack (in 2010) of the software, it was quickly patched, and there has never been a repeat. So people are confident that the algorithm is secure.
- it is the most decentralised
There are more miners running the bitcoin code than any other cryptocurrency, because 51% of them have to agree to a change, that means that it is unlikely to have one mining group deciding a change and implimenting it against the wishes of others (as happened recently with Ethereum classic)
- it is the best known and most widely accepted
Almost everywhere that takes crypto in any form will take bitcoin, which means that it is the easiest to use. It also has the most community support, with "how-to" videos, guidance, FAQs galore, so its the easiest place to start. No other crypto has the kind of community support that bitcoin enjoys.