Memory requirement >2G for composer installation

I am trying to install D8 with composer (using drupal-composer/drupal-project) on SiteGround (max 1G memory) and A2Hosting (max 2G memory) and am getting memory errors, as per example below:

santisch@nl1-ls3 [~/public_html]# composer create-project drupal-composer/drupal-project:8.x-dev d_test4 --stability dev --no-interaction
Installing drupal-composer/drupal-project (8.x-dev c1e2b6e6b32d51e75321d76c503714d8515e2420)
  - Installing drupal-composer/drupal-project (8.x-dev c1e2b6e)
    Cloning c1e2b6e6b32d51e75321d76c503714d8515e2420

Created project in d_test4
> DrupalProject\composer\ScriptHandler::checkComposerVersion
Loading composer repositories with package information
Updating dependencies (including require-dev)
  - Installing cweagans/composer-patches (1.6.5)
    Loading from cache

  - Installing composer/installers (v1.6.0)
    Loading from cache

  - Installing composer/semver (1.4.2)
    Loading from cache

  - Installing drupal-composer/drupal-scaffold (2.5.4)
    Loading from cache

...

  - Installing doctrine/common (v2.10.0)
    Loading from cache

  - Installing asm89/stack-cors (1.2.0)
    Loading from cache

  - Installing drupal/core (8.6.4)
    Downloading: 25%          
Fatal error: Allowed memory size of 2147483648 bytes exhausted (tried to allocate 6291488 bytes) in phar:///opt/cpanel/composer/bin/composer/src/Composer/Util/RemoteFilesystem.php on line 280

Check https://getcomposer.org/doc/articles/troubleshooting.md#memory-limit-errors for more info on how to handle out of memory errors.santisch@nl1-ls3

I was able to install earlier versions of D8 with composer on A2Hosting. It appears that Drupal/core is (too) large now. On SiteGround I am currently stuck with D 8.3 and an old composer installation.

Can anybody confirm that >2G memory is required for newer D8 installations? Are there any workarounds possible to remain within the current hosting plan? Can the core be split up for a less memory intensive installation?