I wonder how they managed to even expand out in the early caliphate days in the first place. Even with the exhausted empires they went up against surely they would've been not much at all?
Firstly, because they were in the middle of an area populated by other Arabs, who were also garbage at war. The playing field was level.
Second, Both the Parthians and Romans were both too exhausted to respond appropriately.
Both empires were also dealing with internal issues and some desert wasteland border areas were not a priority. Initially concerned about provoking the other into another costly war, and reports showed the otherside getting hit as hard as they were, so the general response was "Let them run wild for a bit, when we're ready we'll organize a campaign to kick them out". The other key point is the latest dust up had depleted local treasuries and depleted local mercenary organizations. When the Arabs showed up, the usual response of "just hire some dudes to chase away the attackers" wasn't an option.
If Mohammed had tried his shit earlier, it wouldn't have worked. He knew he could away with it because his trading contacts told him exactly how fucked the local empires were and there was an opportunity.
Third, because they coopted local rulers and populations. Mohammed's message of religious and ethnic tolerance was very attractive for cities that had been getting traded back and forth and having pogroms. All of the most impressive early Muslim victories involved some level of deception, or a disaffected local using the Arabs as a way to settle scores. They were doing hit-and-run like they'd been doing for generations, just getting local rulers to swear alliegance instead of fucking back off into the desert.
Fourth, the Caliphate was already starting to flounder until military leadership was taken over by non-Arab muslim converts who had no patience for Typical Arab Behavior. There was also alot of hiring mercenaries that went on.
And as
@FILTH Tourist points out, in the early rush the there was a lot more to gain for the average fighter, namely a share loot and spoils, plus the opportunity to rise in station if you were a good soldier/leader. That shifted as the number of muslims increased and eventually all merit-based compensation dried up, and those at the top were interested in remaining at the top.
FLIR would eat your lunch then. You can't just dissipate that amount of heat from the turbines that quickly.
Depends on terrain. In the desert, yes. in open field, yes. But IR scopes are of limited utility in forested area like Ukraine or South American jungle.
But that depends on someone out there looking. Again you are really, really underestimating how important listening is for detecting incoming armor.
I recommend you leave the urban bugman hive for a bit and realize when there isn't any traffic around inuring you highway sounds, you can hear an 18-wheeler for miles.
