Why does MSSQL have gaps in an auto-increment identifier?

Question

SQL Server

There is a table table with autoincremental primary key Id. Operations INSERT/UPDATE/DELETE are not performed on it in principle.
The maximum Id in the database is 6, when adding, Id 109 was issued. If the database was restored from backup, then there were always exactly 6 records in it.
Gaps in Id are bad - the capacity decreases (for this table it is not critical, but there is another one, where only 30K records are filled for 100K IDs), unsafe - it opens up the possibility to cheat with records for the past period without the need to delete / replace existing ones.
Actually a question, in what a rake? :)

Answer 1

www.codeproject.com/Tips/668042/SQL-Server-2012-Au...