That doesn't mean advanced tech. They are probably the craft of designers and builders who spent years and years mulling over a problem and studying the oral and written histories of previous builders. When you have no distractions whatsoever and are left alone with your work for years at a time you will come up with crazy ideas, unexpected solutions and masterful levels of craftsmanship. It's the same with ancient astronomers. It's only impressive to us because we are surrounded by endless distractions and end up creating mediocre works in comparison.

Note you should study the history of the pyramids. They evolved over time as the Egyptians perfected their craft. For example there are the stepped pyramids and the bent pyramids which suggest clear evolution in the perfection of pyramid design (and they are all several centuries between each other). If we had high tech then the prototypes would probably have been thousands if not tens of thousands of years older than the traditional pyramids we are familiar with (if they would have even of existed at all).