In this case I would say that you are not comprehending what is meant by the term "environment".
In the case of forklift seating, the term environment means:
An operator mounts and dismounts the truck numerous time in a daily work shift or tour of duty.
Driving/operating a lift truck is not the same as driving a long haul road truck, or even a piece of construction equipment.
Driving a long haul truck or construction equipment usually entails climbing aboard and sitting down in the seat, and then remaining seated until break time or other stopping point.
Driving a lift truck usually means you climb on and get seated, move a bit of freight, then dismount to scan bills or check something else about the loading/unloading/stacking process, check with a supervisor, etc, etc, etc.
The fact that your thoughts (when seeing the term "environment") went straight to other definitions demonstrates that you are clearly engineer material, for keeping seat quality at "status quo". That was intended to be slightly humorous, but with a grain of reality in it.
The longest lasting, most durable seat covering I have encountered turns out to be cloth fabric, not vinyl.
Wise (brand) has a seat called either Durawear or Duraweave (not sure which is correct) that is cloth and we have seen some of those seats go 20,000 hours without busting open.
Michigan Seating also has a cloth covered seat called Modura that lasts longer than a Michigan seat with vinyl covering.
The Michigan Modura has not matched the longevity of the Wise Durawear in our fleet.
But......replacement seat cushions are available for the Michigan Modura (and vinyl as well) whereas the Wise product must be replaced as a "seat assembly" when cushions are worn/torn.

What type of environment?
I'm a field service technician so I deal with all environments.
My statement was directed towards any seat made in today's market.
The costs of materials and assembly labor and the safety device factor has driven the price through the roof imo.

Can you build an adjustable suspension seat with hip restraints, 250 lb weight capacity, durable enough to last more than 6 months without tearing up, seat switch and seat belt switch for less than $600?

None of the seats I've encountered have ever held up very well. I service industries ranging from small- mom & pop stores to manufacturing plants. Doesn't seem to matter the brand (aftermarket or manufacturer original)- they all fail within a short period of time. The vinyl covers split open, then the foam comes out then- game over.

Thanks for responding, what type of environment do you work in?

Are there any more options that you could add to a seat than what is already out there on the market today? Probably not.

My biggest complaint is the quality
Make a seat that won't tear up and can actually hold up to the environment they are subjected to and i'll say it would be worth the money it costs to buy one.
These engineers don't seem to be living in the same world i do cause some of the junk i've seen them coming out with is made rediculously cheap for what they cost the consumer.

Thanks for the great info.

The only issue I have with seats for lift trucks is that the seat frames seem to have been designed as if they are going to be placed on a table top, with nothing behind the seat tracks to obstruct the tracks or seat when trying to adjust for increased leg room.
The problem is that most lift truck OEMs now have a "bowl shaped" hood, or bonnet that the seat is mounted onto.
The bowl shape is apparent more behind the seat due to the fact that the radiator (on ICE powered lifts) is higher than the top of the hood where the seat mounts.
Because most seat frames just seem to come straight back and end right above the rear end of the seat tracks, the bottom rear edge of the seat and the end of the seat tracks encounter the bottom curvature of the hood in that bowl shaped back end of the hood, severely limiting how far back the seat can actually be adjusted.
This is a real problem for operators who are tall/long legged.
On some of our trucks we use an after market seat made by Sears Manufacturing (not Sears-Roebuck) that addresses this issue cleverly.
The seat we use made by them is a one-piece, steel stamping comprising both the seat bottom and the seat backrest.
The stamping is curved where the rear of the seat bottom turns upward to form the seat backrest.
This curved configuration cooperates nicely with the bowl shape of the seat cavity of the hood and thus permits the seat to move back further than can be done with standard OEM seats.
I doubt that extra leg room was their goal when designing the seat, but it sure does work well to give about 2" more leg room than the OEM "square frame" 2 piece seats.
The only drawback with these 1 piece, non folding seats is that they cannot be used easily on an LPG truck unless the LPG tank either swings out of the way, or tilts back to allow the hood to be raised for maintenance.