Hi Michel,
If your question is directed at WGT I apologize for jumping in... I do not speak for the company, their staff, customer support etc.
In short (based on my experience): yes.
Longer answer:
1. Performance level (precision, forgiveness, spin etc.) between your starter clubs and what is available at your level 90 is huge. Simply do a comparison in the pro shop e.g. a value near 0 vs. a value near 5 are at opposite ends of the scale.
2. If you just buy better clubs you will not see any performance benefits without upgrading your starter balls. Search for equipment advice (clubs AND balls) for what is best at your level and tier. Like other situations you get what you pay for.
3. I find the physics of the game to be good overall. Your poor "software" experience is probably due to continued use of starter equipment and starter balls. Very few are able to advance to the higher tiers with this combination.
The software is often blamed because of bad (unexpected) shot results, even with excellent equipment. But performance is based on a statistical model with a fair amount of shots landing at or near the edge of an expected area circle (or some other shape) and a few times waaay outside of this area. Many don't like this model, but it seems to inject enough chaos to keep things interesting and approach the unpredictable experiences of the real game.
-Keith