Why are mountain peak elevations not shown on US Topo maps?

The USGS doesn't have specific data for current mountain peak elevations other than what exists in an  Elevations and Distances in the United States booklet. To determine an approximate elevation at a specific point, use the spot elevation tool query in the in  The National Map Viewer or search the “Summit” feature class via the Geographic Names Information System (GNIS)  Search Domestic Names...

There are no official definitions for generic terms as applied to geographic features. The  Geographic Names Information System (GNIS) utilizes 43 broad categories of feature classes defined solely to facilitate retrieval of entries with similar characteristics. Go to GNIS Domestic Names Feature Classes to see the full list. These categories generally match dictionary definitions, but not always...

The U.S. Geological Survey (USGS) has been the primary civilian mapping agency of the United States since 1879. Some of the most well-known USGS maps are the 1:24,000-scale topographic maps, also called 7.5-minute  quadrangles. In 2009, the USGS transitioned from our hand scribed historical topographic maps to US Topos, which are computer-generated on a regular schedule using national databases...

Historically, USGS topographic maps were made using data from primary sources including direct field observations. Those maps were compiled, drawn, and edited by hand. By today's standards, those traditional methods are very expensive and time-consuming, and the USGS no longer has funding to make maps that way. A new USGS topographic map series was launched in 2009 and branded " US Topo." Though...

The original USGS 7.5-minute (1:24,000 scale) Historical Topographic Maps (produced 1945-1992) included feature classes that are not yet shown on US Topo maps (produced 2009-present). Examples include pipelines, power lines, survey markers, many types of boundaries, and many types of buildings. The USGS no longer does field verification or other primary data collection for these feature classes...

US Topo maps are updated on a three-year production cycle (maps covering one third of the country are updated each year). The US Topo production schedule follows the U.S. Department of Agriculture's National Agricultural Imagery Program (NAIP) collection schedule. This does not include US Topos for Alaska, which are on a different schedule. The linework features shown on the maps are generated...