Its all about the long run and being sustainable, most of the English clubs are not sustainable business models, they just have bags of money behind them and the safety net of huge TV money. As you have seen with Rangers up here, even big clubs can go under if not run properly, and just look at Anzhi and Malaga to see how a Man City situation can quickly turn into a mess.
Southampton are doing well, probably above expectation, and they are doing it while turning a profit and putting quality players on the pitch, dont think you can ask for any more than that.
Eventually it will all collapse and when it does yous will be in a better position than most.
Celtic, historically and fan base wise, are a bigger club than about 98% of English clubs and we can only dream of spending 5m on one player. But it makes it better when we get those big results in the Champions League because we are doing it from a massively disadvantaged position.