According to Cloudflare, the site has had around 30k unique visitors in just the first 3 hours since the link was posted here.

It's my site, yes. It's on a VPS which usually has far more resources than required. I really wasn't expecting to get everyone's attention.

Websites often went down under load 20 years ago too but people were far more quick to think it was their own connection on the blink.

Yes, sites were much better engineered too, with smaller and less rich and less dynamic payloads, but don't count out a change in expectations along with it.

Yes, it is magnitudes more inefficient, with large JS payloads, slow APIs, and underpowered cloud hosts.

The blog is using cloudflare and it is very easy to setup caching rules to optimize the site.

Sadly I have been noticing non optimized sites at lot more now.

There are a bunch of tradeoffs--cost, cost predictability, control, redundancy, flexibility, etc. Money isn't a magic wand as you say and, honestly, I'm not sure how much extra I would pay in general on the off-chance that a blog post might go viral every 10 years--if that is indeed the tradeoff.