In technical terms what we're describing with the word "throw" usually is a matter of SPL at distance. Barring reflections and interference, sound loses energy at a rate of 6dB per doubling of distance and that affects all subwoofers equally. Individual, portable subwoofers can't be "long-throw" by virtue of the fact that they are not large enough to produce meaningful directivity throughout the subwoofer frequency range. Significant directivity is achieved when a dimension of the radiating area is greater than or equal to the wavelength being produced. Therefor it occurs at higher frequencies before lower frequencies, so it's possible for a 36" wide box to provide reasonable directivity at 187Hz (not subwoofer range) and marginal directivity at 94Hz (not quite subwoofer range) but effectively no directivity as frequencies extend much below that.
A subwoofer that operates from 80 Hz down to 25Hz, as most of ours do, are radiating frequencies with wavelengths from 14 feet up to 45 feet. (4.2m to 13.7m) Thus one of our larger cabinets could provide marginal directivity at 80Hz but no appreciable directivity on down from there. Even at 80Hz, there would not be sufficient directivity to be called "long throw". And our subwoofers aren't particularly large or small relative to other portable subwoofers, so the same rules would apply to any box of similar dimensions.
If a box is designed/tuned to be particularly loud at a particular frequency, it will be perceived to be louder at any distance at that frequency. If that frequency is high enough to be within the range where it can produce limited directivity, it will benefit from an increase in measured/perceived output, on axis, in that range. (Consequently it will be perceived as having less output when off-axis.) Every sub box that I've ever heard to be described as "long-throw" was particularly more sensitive at higher frequencies than lower ones. Boxes that are particularly effective at upper-bass frequencies can also benefit from the limited directivity they can provide at those frequencies, making them seem to be very loud and "long-throw" but at the price of flat frequency response and low frequency extension.
A box that produces a broad range of frequencies at the same level may produce less SPL at a specific frequency (compared to a peaky box as described above) but it will transmit the same range of frequencies at the same level at any distance. Flat frequency response is a design choice that precludes tuning for maximum output at a specific frequency. In the design process, the more you're willing to give up in low-frequency extension, the more output you can achieve further up the spectrum. Also, the narrower the targeted operating bandwidth, the more peak SPL you can achieve. Deeper and smoother are fundamental goals for BASSBOSS subwoofers, so any one-note-wonder has the potential to produce a higher SPL at it's one note forte.
The only way to achieve directivity at subwoofer-appropriate frequencies is with an array of boxes. It would be inappropriate to describe the subwoofers in such an array as "long-throw". The array may qualify, but the individual parts cannot unless they are impractically large.
There are two possible conclusions to be drawn from the physics: