There are a few combined cycle GT power plants in the US (more in Europe), but the vast majority of gas turbines are used for cycling and summer/winter peak power. It is not cost efficient to use a recovery boiler in that type of service.
And in the US at least combined cycle GT plants have proved operationally difficult, with turndown and stability problems often requiring the use of duct burners to keep the boiler side stable (there goes the efficiency) and high forced outage rates on the boiler. I've seen a lot of large GT plants (50 - 150 MW) with space on the layout drawings for "future HRSG". That's where you park your truck.