Not at all. A shuttle is a gear shift machine with a hydraulically actuated clutch(es). Basically an evolution of an old manual crash box.
A HST is a hydraulic pump attached to a hydraulic motor. Most don't even have a clutch except for the PTO.
A geared machine is about 15% more efficient than a HST. Better for farming, less precise though. Personally I happily pay the HST tax for precision of operation. I get more value from that than I would the lower operating costs of a geared machine.
They can make huge 1,000+ HP HSTs. And do for dozers & such. The market segment of 60+ HP tractors just prioritizes efficiency over precision & ease of use of a HST. Not an unreasonable choice by any means.