There is one chart everyone should be watching: hashrate.
Hashrate can best be understood as the total processing power dedicated to the Bitcoin network. A high hashrate indicates that the network is secure and that miners are still actively participating, even during a downturn in price. A significant drop in hashrate could signal that miners are losing interest or becoming unprofitable.
The units of measurement for hashrate are hashes per second (h/s).
Glassnode is a great resource for all things on-chain.
Key Takeaways:
Bitcoin's total hashrate is nearing an all time high.
The 30 Day Change of Hashrate Data Set is at a very extremer outlier point.
Seeing such a large shift in total network participation, one must ask: why?
Possible Etiologies:
Bitcoin's recent price appreciation has shifted margins closer to neutral/profits. Economics dictates that any miners should (in theory) take the opportunity if available.
Global energy challenges are starting to dissipate. Although not alleviated, there is a net decrease in energy related commodities.
New technology has become available which offers more powerful processing. ASICs are the typical Bitcoin Miners and the new models are starting to deliver world wide.
Frankly, a combination of the above reasons is the most plausible.