I totally relate to E27007. My previous flat was a leasehold where the leaseholders had previously brought out the freehold (26 flats). We had no management company - instead the leaseholders did all of the work ourselves.
At first it was great - £1/day service charge and we had a big sinking fund. One person did the accounts, one person dealt with the paperwork of flat sales, one person maintained the gardens, one cleaned the communal area, one cleaned the gutters and painted the exterior fascias and doorframes etc. This worked well as a lot of the leaseholders were retired professionals with the right skills and a lot of free time and it had a nice really community feel.
Then some of the long-standing residents moved away and sold their flats to buy-to-let landlords. Landlords and their tenants never showed up to any meetings, never really engaged with emails and of course they and their tenants never pitched in to do any of these chores. We had some flats with multi-year debts on their service charges. More work fell on handful of people remaining. By the time I sold up one person was basically doing everything, all for free, except gardening and cleaning communal areas which we contracted out. I wouldn't be surprised if they've engaged an external management company to manage the whole block now so this guy can finally enjoy his retirement in peace.
This structure is practically the same as a commonhold. It sounds good in theory, but it relies on everyone pitching in. If your neighbours can't be bothered, it just doesn't work. Even the paperwork can be a huge workload and legal liability (directors' insurance, building insurance, fire safety reports, electrical safety, dealing with conveyancors every time someone in the block sells up, accounts, meeting minutes, flammable cladding reports etc, as well as liasing as the middleman between leaseholders, their tenants, insurers and tradesmen whenever a leak from one flat causes water damage below), so why not pay someone else to handle it.