The 130 is still around because it is a good all-around siren that meets the basic requirements of most systems. It's able to compete price-wise with other mile-range sirens and has a *rated* SPL advantage over everything else on the market at 130 dBc at 100 feet. The Equinox is a lower-cost option if you don't care for the SPL as much, and if you want more range, they give the 508 as an option with a slightly higher price tag. That pretty much sums it up; you pay more for the range same as with the Tempest lineup. Equinox < 130 < 508-128
Arguably, they all have advantages that make them better depending on the area. Low-pitch sirens dominate higher-pitched ones in rough terrain. Sirens like the 28/2910 and 16V1T-B will get snuffed out by 2001s up close, but they outrun them in my area since I live on the Fall Line in the Georgia/Alabama area, which has numerous valleys and hilly landscapes. It makes enough of a difference that it would make more sense to go with an Equinox down here over a 130, as the lower pitch can compensate for the difference in SPL and allow for them to perform about the same, saving some money in the process.
On flat land, however, 2001s will probably outperform them since there are fewer obstacles that the sound has to fight while traveling through the air.