Bitcoin in its current state is not capable of supporting world-wide adoption of Lightning. Other solutions will need to be developed.
Just to put some numbers on this: Let's assume all the following (which is completely unrealistic):
- Everyone uses Taproot
- Every channel opening transaction is one-input-one-ouput
- Every transaction being made is a Lightning channel being opened, and no one makes any other type of transaction
- Every block is optimally full
- Everyone only opens a single channel which they keep open forever
Even assuming all that, then at most you can open 9,000 channels per block, meaning it would take 17 years just to let everyone in the world open a single channel. As soon as you consider that obviously some people need to have multiple channels open for Lightning to work, and obviously people will want to close channels, open new ones, top up their channels, and so on, then that number increases exponentially.
Lightning is great, but it cannot support global adoption without further changes to the base layer.