just my take on futures... The one hose, 2 stage open circuit regulator has been around for over 40 years that I’m aware of. My first reg was a USD piston calypso IV and while there have been refinements, the basic design hasn’t changed much. The tech has reached maturity, much like film cameras by the ’90’s. Then comes along cmos and ccd imagers, and an entire industry turns over in 10 years. The problem will be what is the driver? Divers aren’t staying away because they need a big tank that has to be refilled every 30-60 minutes of diving. Unless there’s some unforeseen breakthrough, I think all you’ll see are incremental changes. I do thing you might see the full face mask/reg/comm unit driven down to more reasonable prices.
The breakthrough might be some easy/reliable/cheap to maintain and replenish Closed Circuit Rebreather system. It would have to compete with roughly $10/hour and $500/rig current prices. Last I checked CCR rigs started around $9k and then you still needed O2/air/absorbent