At the end of the day, it is about managing risks. If I really want a toy, then I prefer to buy it sooner rather than later. If it's a toy that is lower on my wants list then I'll put it off and accept the risk that I may miss out on it. But we're talking about, really, independents charging marginally above RRP. The max RRP for a Deluxe is $30, so paying say $37 for a Deluxe means $7 above RRP. Unless you're a full time student, this probably isn't going to break your finances. I can afford this, but it means that I get the toy sooner. I expend more money but save time. Others may like to expend some more time if it means saving a bit more money - fine. But you're either spending money or time. Either way there's a trade-off.
There are people who pay WAY above RRP for older toys. This means that you got the toy much later at a much higher price - expending both time and money. There's no trade off here, and IMO this would be a greater source of lament. And I have met a number of collectors who are financially compromising themselves by collecting like this. I recently spoke to someone who admitted to buying an old toy at way above RRP and spent the next month eating Mi Goreng for breakfast, lunch and dinner. There are people who admit that they can't afford things like furniture, cars, going out, travelling, rent etc. because of how much they're spending on toys - and these are SINKs!I've even met people who have families who spend beyond their means on toys.
How much people want to spend on toys is up to them, but IMO it ought to be financially sustainable. Yes, I paid independent prices for my POTP, but it hasn't financially affected me. It's something that I can easily afford and saves me time.