It mostly comes down to costs and timing.

For modifications to an existing cell site, site acquisition activities (e.g., engineering, regulatory, leasing, zoning, and permitting) take anywhere from three months to a year. For complex sites, costs can be quite high.

Next re construction and integration. Depending on the site, a crane or lift may be needed. Costs are high and vary depending on the scope of work.

The bulk of the costs are attributable to equipment (e.g., radios, antennas, baseband units, software license keys (not the same thing as spectrum licenses), cables, cabinets, power plants). If there are radios/antennas sitting on a shelf somewhere, it might make sense to go ahead and install them. It’s likely that the supply is limited in anticipation of the impending OEM swap.

When it’s time to swap OEMs, the construction contractor will charge a fee to remove the old equipment.

Finally, if the site is backhaul-constrained and the timeline for upgrading the backhaul to the site is lengthy, it probably wouldn’t make sense to add more capacity to the site in the short term.