Integration tests are needed and simple
The pyramids in Egypt were built in ancient times. We still admire them today, appreciating the craftsmanship and hard work of their builders. However, do we build houses from giant stone blocks today? Not likely, current times bring other needs and offer other technologies.
Pyramids of testing were also built some time ago. We admire legacy projects with a rich set of tests, but do we create projects today the same way we did 10-15-20 years ago?