I've noticed that the automated buys I have set up typically fail when the price is low and succeed when the price is high... according to Coinbase this is due to my bank.

But now when the price is high Coinbase can't manage to scale the website so that people can sell?

It would not be hard for coinbase to engineer a meta-strategy using targeted service failure to extract additional profits from the ecosystem's obvious trends. Not saying this is going on, but there are now to indications that this could be happening.

Someone is intending to buy at $12K so you fail the transaction for 3 hours if your simple model expects a higher price tomorrow (meanwhile buying some coin at market to use later when you succeed the transaction).

Yeah I think its just poorly managed with all the traffic thats been cluttering the systems

It seems Coinbase struggling to cope up:

$0000 - $1000: 1789 days

$1000- $2000: 1271 days

$2000- $3000: 23 days

$3000- $4000: 62 days

$4000- $5000: 61 days

$5000- $6000: 8 days

$6000- $7000: 13 days

$7000- $8000: 14 days

$8000- $9000: 9 days

$9000-$10000: 2 days

$10000-$11000: 1 day

$11000-$12000: 6 days

$12000-$13000: 17 hours

$13000-$14000: 4 hours

$14000-$15000: 10 hours

$15000-$16000: 5 hours

$16000-$17000: 2 hours

$17000-$18000: 10 minutes

$18000-$19000: 3 minutes

No, it's just poorly managed. Use Gemini, which is 10 faster and much cheaper.

yes https://status.coinbase.com/