Lots of interesting replies so here is my reply.

Pow coins are mined with power.

In my case I mine

Ltc/Doge
Btc
Eth

so I look at all of my gear and always study price of earnings per watt.

I have been mining a long time I am not a huge farm but my gear is paid off.
My power cost is fully managed.

So for 2000 watts  I pay 6 cents. x 24 hours is $1.50

what do I earn.

if i run an s17 pro set to 2000 watts it does 55th at 21 cents a th that is 11.21-1.50= 9.71
if i run 13 3060ti gpus set to 2000 watts it does 780mh at 10 cents an mh that is 78-1.50 = 76.50

for the same power.

now if I believe in eth I wont mine the btc I would double up my gpus.

but if I believe in btc I would mine both and dump the garbage eth for btc.

since all my gear is paid off I only need think of watts and fiat earned.

so I swap all my mined eth for btc.

this helps lower the price of eth as I am dumping it asap
it helps raise btc as i am creating a demand for it.

So what do i do if btc crashes and eth crashes.

I may panic and do eth to fiat. still hodl the btc.

add in my doge/ltc and those ratios favor mining doge/ltc not btc.

Since my bias is btc and all the coins above are linked by power to earnings they are all going to move up and down close to each other.

When they get out of synch crashes happen.

eth pays too much per watt
doge/ltc pays too much per watt
btc pays too little per watt.

if true btc will rise a bit and the others will drop a bit.

essentially they offer very similar features at least doge,ltc,btc do

eth is another animal if it was not controlled by mr v i would like it more. so the good features are lessoned by mr v having too much power.

this is how four pow coins are link via earnings per watt. which binds the prices somewhat together.

obviously pos are not really accounted for in this explanation but they are about as stupid as nfts, charile bit my finger sold for 720k yeasterday.