Not sure why some people are calling it dead already.
1. While he's a core dev, he's definitely not the only dev
2. Lightning has never been perfect. But while it technically works, it's simply not ready yet. There's a reason why I never recommended it to normies yet as of yet. But, let's not forget that —
3. Software can be improved
1. There's always this strong vibration if the core developer leaves. He might not be the finest developer, but when the soldier who pulled the first shot is down, the zeal to soldier on is always not assured.
2. No technology ever came in a perfect form, even the bitcoin is still in beta version. Continuing on decentralisation will do the wonders.
3. Yea, we are expecting improvements but I lost some confidence in LN during the event of mempool congestion that skyrocketed the transaction fees. At that time that the LN was needed most, it didn't help much.