LN solves Bitcoin scalability issues
Not entirely. It solves scalability issues at the current number of users, but to scale it up to global adoption needs other technology which is built on top of Lightning, such as channel factories.
but the reason why LN failed to take off (which I infer from your last explanation) is since most of the transactions are managed by LN not by the bitcoin network.
I don't think so. Rather, it is still in early stages of development.
If solving scalability issue alone can take you to moon then there are thousands of tokens that are super fast when compared to Bitcoin.
As BlackHatCoiner points out above, a faster initial confirmation is not necessarily better. Take a look at this site:
https://howmanyconfs.com/. Take a look at BCash for example. You might think the big blocks are better since everyone can get in the next block. But actually, the blocks are almost empty (a few dozen transaction each, compared to 4,000 transaction per block for bitcoin's smaller blocks) because no on is using it, bigger blocks make the system more centralized, and it takes
over 12 days to reach the same amount of security as bitcoin reaches in an hour.
It is trivial to launch a coin with instant transactions. All you need is a centralized spreadsheet which can update balances instantly. That doesn't make it a good coin.