I tend to buy what I need in terms of cameras and lenses based on what I shoot most of the times and I rent/borow what I like but I don't need so often. As long as I have renting options and a system with a solid lineup of cameras, lenses and accessories to choose from, I'm a very happy guy with zero pressure to change systems. I rather pay 15$ to rent for 2 days a 1200$ Tamron 150-600mm G2 lens or to pay 35$ to rent a 6000$ Canon 300mm f2.8L lens for 2 days if I go out to shoot wildlife or other stuff than buying these lenses.
For me this approach works best. I can shoot with top of the line lenses when I want/need without spending thousand of dollars on gear that I need once in a while.
For vacations, portraits and corporate events I need only the 4 lenses that I own: one fast wide angle zoom lens and 3 prime lenses.