Bitcoin is not just software.
Research behind implementing Schnorr signatures, lightning network, confidential transactions, efficient confidential transactions (bulletproofs), is bleeding edge research in cryptography mixed with whole bunch of other fundamentals.
Nodejs required practically no academic research while bitcoin needs it heavily today still.
For example, you have papers like above being published in the context of bitcoin. 60 pages of untrivial math, and that's just one idea of how to scale bitcoin.
The above is a proper paper on how to do math for a DAG based protocol.
Serguei Popov, the research mathematician behind IOTA DAG based protocol, claims that it is impossible to make proofs behind the tech. 
A great DAGchain paper is "SPECTRE - Serialization of Proof-of-work Events: Confirming Transactions via Recursive Elections". Its peer reviewed and contains rigorous security proofs.
> Not really. The odds of an attacker successfully generating a double-spending block remain the same with a lower block interval. Many alternative cryptocurrencies have far shorter blocktimes: Litecoin has 2.5min blocktimes, and ethereum is less than 30 seconds IIRC, and they don't have problems with rampant double spends.
I based my statement on the following paper: Serialization of Proof-of-work Events: Confirming Transactions via Recursive Elections: https://eprint.iacr.org/2016/1159.pdf
Unfortunately, recent research has shown that the Nakamoto consensus has severe scalability limitations , , , . Increasing the system’s throughput (either via an increase in block size or block creation rate) comes at the expense of security: Under high throughput, Nakamoto’s original guarantee no longer holds, and attackers with less than 50% of the computational power are able to disrupt the system. To avoid this, Bitcoin was set to operate at extremely low rates. The protocol enforces a slow block creation rate, and small block sizes, extending the blockchain only once every 10 minutes (in expectation) with a block containing up to 1 MB (roughly 2,000 transactions). Users must thus wait a long while to receive approval for their transfers.
Regarding litecoin: litecoin does have a lower block creation time of 2.5 minutes - however if you look at the average block size of litecoin it averages around 15kB, compared to ~950 kB of bitcoin (basically exhausting its 1MB limit): https://bitinfocharts.com/comparison/size-btc-ltc.html Considering the litecoin network operates way below its maximum capacity a double spending attack is indeed unlikely. However whether that security would hold up under full load remains to be seen.