For years now, the largest tower operators in the world have been looking for business models to drive their next wave of growth, especially in markets where infrastructure build-out, combined with scaling-up through consolidation, are suffering from laws of diminishing returns. In-building infrastructure, shared small cell RAN, edge compute, fiber and private networks have all been on the agenda, but some of the most active towercos in exploring new markets are now retreating to their core business. This was seen at Cellnex, Europe’s largest pure-play towerco, at the turn of the year, while its major rival, Vantage Towers, has also stopped talking up diversification plans. Now, under pressure from activist investors, the USA’s Crown Castle also seems to be rowing…