Lifestyle business beats a startup, until it doesn't. I'm the example. Ran a category leading website for years until I was demolished by a fully focused bad ass team and thrown out of my leadership position. Ultimately, I was forced to sell out at a much lower valuation than I'd have if I were totally focused.
It could vary on niche and industry. But one can't generalize it one way or the other.
If you have a great position in a big sector and you don't go for the kill, someone else will and your lifestyle business would be likely chewed up by competition. If it's a business with an intrinsic moat(think a retail store in small tourist town), it's likely to sustain.
Take frequent breaks while running a bad ass startup, but don't for a while think that you can let the ball drop.