My suspicion is that:

1.) The price of Bitcoin will skyrocket by that point, making even small amounts highly profitable for sha256 miners who are still mining Bitcoin.

2.) The concentration of miners will diversify to other cryptos that are looking to take advantage of the high amount of sha256 mining power that is now available and interested in mining new currencies.

3.) Electricity prices will plummet as new power sources are developed and discovered.

I'm not worried about it all.