Right now I don't think the current amount of engineering interest in Bitcoin is particularly healthy.  Many long time contributors, including myself, have essentially stopped contributing for a variety of reasons (including uncertainty around political disruption of deploying even fairly boring new consensus changes, concern that too much bitcoin hashpower is controlled by bitcoin adversarial parties who would attempt to block protocol improvements, etc. on top of more generic factors).  Lightning is also easier, faster, and often more interesting to work on and so it has diverted a lot of new blood.