Debunking "hashrate is higher, so security is higher"

Lately in a few discussions I've seen people arguing that because Bitcoin's hashrate is higher than X weeks/months/years ago, Bitcoin is more secure or harder to attack. It's a very dumb argument, and I'd like to debunk it here so that hopefully we can raise the level of discussion about crypto.

First, some numbers (all from blockchain.com)

Bitcoin's current market cap is ~$370 bln. In December 2017, it peaked around ~$323 billion.

Bitcoin's current hashrate is 222m TH/s. Bitcoin's hashrate during the 2017 peak was 13.8m TH/s.

Bitcoin's current total mining revenue is ~$16.5 mln. At that December 2017 peak, ~$45 million.

What am I getting at? Market cap is up about 10%. Mining revenue is actually down by 50%+. Yet hashrate has increased about 1500%. Do we conclude Bitcoin got 15x safer, despite miners being paid out less therefore most likely also investing/spending less?

Hashrate is just one metric. If you make your walls 10 meters high and ladders reach just 5 meters high, you're pretty safe. If two years later your walls are 20 meters you can say "I'm twice as safe", but if ladders now reach 18 meters high then no, you're really not.

Another example. Let's say by some form of magic a new ASIC is developed that produces 1000x more hashrate at the same cost as current ASICs. Hashrate shoots up by 1000x. Is Bitcoin 1000x safer?

The important metric is the cost to attack the network. If ASICs get more efficient, provide more hashrate for the same buck, then the network is not safer. If total security spend goes up and instead of it taking $1 billion to get your hands on 51% of the total hashrate it now takes $2 billion, then security has gone up. Hashrate does not exist in a vacuum, and saying that "hashrate is higher, so security is higher" is wrong.

Thanks for coming to my TED talk.

Edit: adding in another way to look at it.

In May 2018, the cost for a 1 hour attack on Bitcoin was $600k (see the link). Checking the website right now, the cost is about $837k. So in that sense it has gotten harder/more expensive, but not the 7x harder/more expensive that the climb in hashrate implies (34,000PH/s to 237,000 PH/s). Market cap climbed from $123bln to $375bln in that same timeframe, implying "security per dollar" actually decreased, but this is of lesser importance I think.