I use the gear I do because it does the job I want it to do, and it does it perfectly (for me).
I have tried other basses (and own a Jazz type and a couple of Stingray types) but a good Precision is the perfect bass for what I want to play and how I want to sound. Similarly with Mesa Boogie. I have had flirtations with other things over the years but have always owned and come back to the brand. In years of touring it's never let me down, and the sound of it makes me smile, even after more than 30 years of using it. The actual equipment may have changed but the core sound hasn't (to my ears).
The same with strings. I have broken just one string in 50 years. That broke as I fitted it. Again, it's a vital component of the sound I really like.
There are plenty of makes that I haven't tried but there's no point. My gut feeling is that the (not insignificant) investment in those rigs has saved me a fortune in chopping and changing over the years.
Of course, you'll see that I endorse some of these things but I was using the gear way before I became an endorsee. That is very much the icing on a very expensive cake! 🙂