It is solely down to investment. This is further compunded by the type of pitch we have. When TTA were all open palms they spent a fair bit on an [at the time] innovative new pitch which, if maintained at around 80% of whatever the full price is, would still be a very good pitch now.
However if you don't keep up with the higher level summer work it will deteriorate faster than a 'normal' grass pitch, especially if you factor in our weather and also playing other sports on it.