That is constantly used as an excuse. The UK also has many airports, but LHR is also continually improving. If the govt. has the intention of making KLIA a premier airport, it can always make KLIA the responsibility of another GLC or private company. Then it will not be distracted.
I have also mentioned it before - although Changi is only one airport in Singapore, the company does manage more than just Changi. It is also an airport design and construction consultant and also manages some other airports overseas.
Also remember, KLIA was a premier airport when it was first opened but it did not improve (or even maintain) its level of excellence. So it is possible to be good, but it would appear that the tidak apa attitude is more prevalent these days.
LHR is no benchmark to follow. Unless, of course, you like astronomical taxes and terrible value.
And let's not delude ourselves into thinking KLIA can be a "premier" airport. It never was and is unlikely to be one anytime soon. The unfortunate fact remains - KUL doesn't have the traffic, yields and resources to compete with SIN. Unless the government is going to tax the living daylight out of each and every traveller (something which you yourself are an opponent of), we can stop dreaming about having the world's largest man-made waterfall in the region's "premier" aviation hub. What some people are forgetting is Jewel Changi is also intended to be a destination for Singaporeans. How many people live within a reasonable radius of KLIA to actually consider going there just for fun?
Sure, certain things can be improved without breaking the bank, like toilets and managing efficiency, but if we're going to turn the fantasies of some into reality, are we ready to pay the price?