US want to project power far away from its shores -> long range, precision strike, long loitering time.
Partly, but I think there also is a feedback loop. Reapers are expensive, so they must reliably reach their targets. That makes them more expensive (need to be faster, more reliable, less visible on radar, etc), so fewer get ordered, so they must get even more powerful and reliable. That makes them more expensive, etc.
Also, being very expensive, you want them to be able to return home after a mission. That again increases weight, costs.
Result: https://en.wikipedia.org/wiki/General_Atomics_MQ-9_Reaper says only 575 got built over a period of about 20 years. In comparison, the USA built about 96,000 aircraft in 1944 (https://en.wikipedia.org/wiki/United_States_aircraft_product...), reaching that total in about two days.
Does one really need to bring along 2,500 kg of ordinance, when we can launch another $50,000 shahed-equivalent at whatever hard targets the loitering drone locates?
I'm not sure if "future" is a good word for the widespread civil unrest, nascent insurgencies, and very normal soft-target gun battles that happen weekly here, but our "US conflict" looks like street-to-street fighting, within our own borders, with people who are already here.
"The avalanche has already started. It is too late for the pebbles to vote." -- Ambassador Kosh, Babylon 5
Being less flip, the pull quote suggests (per my bias) our drone design is as much influenced by how much shit contractors can sell to put on a drone as it is by tactical needs. The kinds of targets that would require one ton of explosive are fixed sites that have been specifically hardened against attack. You'd hope some modern McArthur would look at the situation and say, "Screw it, we will just go around those sites and bomb the hell out of their supply lines with tiny drones", but what the hell do I know?
In short: War is sell.
- Reapers fly at a "medium" altitude, which is up to about 50,000 feet;
- They can fly up to 300mph;
- Despite being relatively high up they are relatively slow so lots of country have the military capability to shoot them down and have done so. This includes Iran and the Houthis;
- A typical payload is 2x GBU-31 JDAM (1000lb each). The explosive payload is roughly half that but these are relatively cheap (<$50,000) because they're barely-guided gravity bombs;
- They will also have 4x AGM-114 Hellfire missiles, which are precision-guided, costs $100k+ each but only has an explosive payload of under 20lb. When people talk about drone assassinations that becccame super-popular in the Obama administration, this is largely what they're talking about;
- You can also skip the JDAMs and just have 8x Hellfires instead.
Now Shahed drones aren't as fast, don't fly as high, aren't as precise and you know they're there (a lot of Hellfire attacks are a surprise). But they're incredibly cheap and they overwhelm missile defences easily just by sheer volume. In fact, we're using $1-4M Patriot interceptors to shoot down $20k drones. Obviously that's not going to scale when Iran can produce thousands a month and the supply lag for Patriots is actually years long. Supplies of certain missile defense munitions are suspected to be critically low already and will take years to replenish.
So where I'm going with all this is that Reapers and Sheheds serve different purposes but however you look at it, a $50M Reaper with $1M+ in munitions is WAY less efficient at deliverying payloads that a swarm of cheap drones, particularly when your enemy has invested a lot in missile defense and your $50M Reaper is vulnerable to air-defense systems from even non-state actors (ie the Houthis).
Put another way, $20k for a 50-100kg payload is incredibly efficient and the US has essentially been forced to evacuate all their Gulf bases because they're completely unable to defend them. Billions in damage has been done to these bases too.
The Reaper just isn't fit for purpose anymore. Use it against a more militarized opponennt (eg Russia, China) and they'll shoot those things down like it was a carnival side show.