@Lalala205 I think you paint quite a jaundiced view of allotmenting 
While I recognise a lot of what you say in terms of the challenges we face many of those challenges can be overcome in time.
We too have a big horsetail problem on our new orchard plot but have plans to deal with it (glyphosate mixed with a bit of washing up liquid).
Heavy clay soil benefits from having a lot of organic matter dug in but we are lazy so pile it up on beds and let the worms do the heavy lifting.
Our polytunnel is of the cheaper type and is now in its fourth year. The greenhouse must be 10 years old if not older and still going strong.
We are fortunate to be on an allotment and smallholding field. This means that some of the plots are effectively small businesses as we are allowed to sell our crops. One plot near me supplies a veg box business, there is also a small pig farm.
Hens break even (I costed them up once) in little more than a year if you eat eggs regularly and are prepared to eat the non layers.
There can be capital outlay for having an allotment but what I see on my field is a lot of reusing, recycling, re purposing. We are an elephants graveyard where old swings, climbing frames and bits of old scaffolding go to finish their days as supports for netting and beans.
The biggest expense in allotmenting is time but that is my own.