Last time I checked 1ml.com (truth be told, I just looked into it), it didn't show any improvement at all in Lightning Network adoption. Actually, the network capacity went significantly down over the last few months. I remember its peak at over 1k bitcoins (still a minuscule amount itself), and now it's at 837 BTC. That gives us a strong push toward the conclusion that Lightning Network is as good as dead so far
Not at all.
Yes, the capacity has dropped recently. No, that isn't a cause for concern. Over the first part of the year,
lnbig.com funded and opened channels to every public node, causing the big increase in capacity. They recently started closing down channels to inactive nodes, which has caused the recent decrease. It's also possible people removed funds from channels to trade as bitcoin's price climbed from $4k to $12k.
Why is this not concerning? Two reasons. Firstly, the only numbers we are tracking here are public nodes. These public nodes are generally used to route your payment through to reach its final destination. We don't know how many private nodes there are, which include the most commonly used Lightning wallets such as Eclair. It is likely there are far more private nodes than there are public ones. Secondly, capacity is not the same as volume. Capacity is needed to route a transaction, but says nothing about the number of transactions or volume of BTC being moved through LN.