Depends on budget. One £3k bike is better than 6 £50 bikes, but an £8k bike (assuming you can find one) is not as good as four £2k bikes.
It all depends on how you ride. I have 3 mtbs, but they are all different. An XC race bike, a trail bike, and a ‘big’ bike which for me is a 170mm Patriot. If you like to DH and also XC race, then you obviously benefit from multiple bikes. If you just hit the local trails, then there’s no point in having many bikes.
why would you want a garage full of Golfs when you could have one 458?
You’d be a fool to buy a garage full of Golfs. Better to buy a Golf, an MX5, a Transporter, a camper van, a Landie, etc etc.