Too opened ended of a question, but in 'old days' it would be a ticket for a new vm, then back and forth between dev and infra to setup the host, deploy the application etc...

If you had a really good team, hours. At most companies, days to weeks. At worst, months.

With a well managed Kubernetes, around 5-15 minutes. Not a theoretical time, I have personally had thousands of devs launch that quickly on clusters I ran.