Bitcoin has already patented the primary idea behind cryptocurrencies
I refer to a paradigm of confirming transactions in a trustless decentralized environment using public-key cryptography. Almost all altcoins are using the same approach (if not all of them), so, in this respect, they are no more than copycats, whether you like it or not. That's why it is impossible for them to effectively compete with Bitcoin. Regarding new great features that worthy altcoins might actually have, they need to be tested by time and real use to be considered for replicating in Bitcoin
That must also be the reason why no other car exists but Daimler-Benz. After all, they invented the internal combustion engine with 4 strokes, and all other cars are just copycats. So they never made it to the market, and Toyota never got beyond a measly market cap compared to Daimler-Benz. Or did it ?
There's still another difficulty with bitcoin: "protocol-stiffness". It is increasingly difficult to modify profoundly the technology of an existing crypto currency, because its value proposition resides exactly in the immutability of its basic principles. The more mature a crypto currency gets, the harder it becomes to change anything fundamentally. This is not true with other technologies, where the first mover often also has most experience in *improving* technology. Bitcoin is stuck with old technology, and it is much harder to get new features into bitcoin, than it is to create a new coin, or implement new features in a young coin that is still malleable enough to accept modifications.
The most striking problems of bitcoin are of course the backed-in limited amount of transactions per second, which seem hugely difficult to overcome. And the transparency of the block chain (in other words, the failure of pseudonymity, because of the networks of change payments, and combinations, which propagate unwillingly a lot of real world knowledge of identities), together with the too simple PoW scheme which has led to ASIC mining and hence, re-centralisation.
That said, because of most of crypto today is speculation on exchange IOU tokens, the actual block chain tech doesn't really matter for the moment. The speculative game that supports most of the market cap of bitcoin and crypto in general doesn't even need any block chain, so the technology doesn't really matter (apart for boasting and hyping). The little use that is really made of crypto can do with just any block chain tech.