I think that there are a few of influences pushing people towards Russian camo and equipment.
Firstly, I think some people are getting tired of running the same old high-speed, low drag multicam MOLLE low-loads as everyone else. THE generic airsofter loadout is a multicam JPC with Crye (or knock-off) pouches plus an OpsCore/Air-frame helmet and a M4A1 SOPMOD/Mk 18 Mod 0/Mk 18 Mod 0/Block II M4/Keymod AR/Tubular Rail AR/Honey Badger/.
Secondly, I think MSW has been HUGELY influential. Their events hit the scene in the last year with a ton of hype and people are starting to pay attention. I noticed just recently that Amped Airsoft has started to carry RUSFOR gear.
Thirdly, the Rushing Russians team has been influential. They are closely associated with MSW.
Lastly, the current conflict in the Ukraine has brought modern Russian gear and equipment into the spotlight.
Personally, I'm all for more kit diversity on the field. NATO multicam versus NATO green versus NATO tan is pretty boring.
As to your point about money spent on kit, players with the most experience and the most interest in military issues tend to have gear reflecting current military trends (i.e. multicam). Newer players who have not invested as much and may very likely be new players with limited incomes are often buying cheaper gear and/or what is available locally to them at surplus stores. This has definitely changed over the years, however. It's super easy for newer players to buy cheap ACM JPCs, AVSs, CPCs; cheap MICH 2000s, OpsCores, Airframes, etc. Even rail systems which only a few years ago were super pricey are available as ACM replicas for sub-$100 prices.
In the past, there used to be a huge green/tan dichotomy with experienced players rocking tan gear and generally pounding the green team in every game. This started to change as green players, tired of getting owned on, started to buy tan gear. In addition, a lot of the experienced guys on MiA participated in Op. Northern Light a few years ago where most of MiA ran OD or M81 Woodland. So a lot of experienced guys with fancy tan or multicam camo went out and bought a green-based camo. So there's been a bit of a diversification of people of different experience levels owning a wider variety of camo.