4 things:
They roll over stuff easier, which makes them feel like there’s some suspension in certain situations, like repeated small rocks or braking bumps. But theres’ no benifit on drops. So an enduro 29er might have 130mm of travel rather than 160mm (I suppose it could be made more progressive too, but that’s an oppinion, not a fact), hence the SB66 Vs the SB95.
The false truth that 29ers are dull an only for XC and not for fun bikes. Therefore prople buy “a 29er” when they mean buy “an XC bike”.
29ers were niche, rigid bikes were niche, ergo there are a disproportionate number of rigid 29ers and hardtails. Probably also stemming from the lack of any compatible forks or frames and the fact they obvioulsy have the biggest advantage (that feeling of a slight suspension) when theres no suspension..
4 they’re heavier, no gettign away from that. FS is also heavier. People have an aversion to bikes over (insert nominal 22/24/26/28/30lb weight here), therefore avoid 29er FS as it’s the heaviest option, despite bike weight having litle or no impact on the climbing speed.