When did Army said they need sasta piston wala engine ? ADE had the freedom to strap anything including Shakti engines used in Dhruv to turn it into a powerful drone like MQ-9.
At least I am not aware of any such requirement from Army (you can correct me by giving source). Also, there are absolutely zero drones in the world who can sustain operation at 30k feet with a piston engine.
There is no hesitation in ordering deshi maal, infact Tapas is already planned to be inducted by Navy & AirForce.
My problem is ADE/HALs constant re-assurance and lobbying with MoD that they will be able to deliver Tapas with the above requirements knowing fully well it cannot compete with similar weight category drones like MQ-9 and Akinci. Even before trials it was pretty evident that under-powered engines will be a big problem in payload carrying capacity, and that it cannot carry anything useful apart from an EO payload.
Tapas is not a competitor to MQ-9, MQ-9 is a different beast. Its capabilites are more matching to TB2. People with low-literacy in defence matters (that includes MoD babus who approve such deals) think Armed forces is throwing a fit when they can buy Tapas. Reason the deal for MQ-9 is not yet signed (and god knows when it will be delivered).