(Bloomberg) -- Billionaires who built their fortunes rolling out wireless networks when debt cost almost nothing are seeing their wealth crimped by higher borrowing costs and caution among money managers on the outlook for the industry.Most Read from BloombergMusk Makes Surprise China Visit in Search of Tesla Revenue BoostElliott Said to Have Built ‘Large’ Stake in Buffett-Favored SumitomoBHP’s $39 Billion Copper Play Was Years in the MakingBlade to Offer Luxury Bus Service to Hamptons at Fare U