A couple of points.
1. Fixed pensions.
Not that common these days (except UK state pension if you live in Thailand), well you have to plan ahead and expect inflation. Just because inflation was only 2% the year you retire doesn't mean it will stay that low. You can easily live 20 years after retirement and in that time everything could easily double in price due to inflation (and, maybe, much more). Anyone who retires to another country with only a fixed income needs either a lot or an exit plan (low balcony?).
2. why so many brits?
Pensions for many Brits are pretty <deleted> (I know!). For those of us who have no partner, retirement in the UK is just a slow death for most - the pension means survival, but all holidays, sports and other leisure activity are expensive. Thailand offers more opportunity to enjoy your sunset years. For me the idea of living in a bedsit with just a tv and a computer for entertainment, and miserable weather, for half the year, was not an appealing prospect. I chose the Thai option.
3. Why complain?
See 2. Low pension, high cost of living means many of us had to budget, have ALWAYS had to budget. Existence was always a bit McCawber like. So 10 baht here, 10 baht there and a bit of shrinkflation means choosing what to go without. Thailand has it's attractions, but why anyone who was rich would choose to retire here is beyond me. If when i retired i had a million pounds i doubt i would live in Thailand - holiday maybe, but live no. I had a nice property in France, and another in Florida on my retirement options, but redundancy and divorce sunk those.
Ok moan finished!