[kigster]

Ruby's performance as a function of infrastructure cost was largely fixed back with Ruby 2.2. Today it's even faster and uses less memory.

The performance problems were 99% invalid database usage, poor or overly aggressive pre-emptive indexing, or bad active record usage.

Developers lacked education in basic database design, and given rails made it do easy, yes that resulted in a lot of slow code and overloaded RDS instances.

But it was entirely possible to build highly scaling rails apps back in 2012. When I ran Wanelo's engineering team we squeezed 300K+ rpm's on a relatively small cloud foot print. It has since been migrated to Heroku.