To be fair, most uk trail centres offer a ride out that doesn’t require a 5K full susser. You can ride most trails centres on any bike. The limiting factors are the speed you want to ride at and the line you want to take. If you want to wobble around half pissed and full of coffee and cake then maybe a 29er is your perfect trail bike. If you want to blat down the downy bits as fast as you can, challenging your capabilities and nerve and that’s what you drive the distance for, then the maybe the expensive bouncer is for you. Horses for courses. Personally I like to do both.