Almost sure the following has been asked before, sorry for that, but couldn't find such info quickly. Sorry.
Playing DL vanilla, newbie. Having made some tech advances, I find that I can no longer build 'obsolete' buildings (such as Basic Factory, but only a more advanced form of factory, which are much more expensive and take a lot longer to build). However, I get the feeling that if it were still possible to build the obsolete versions as well, I would be able to get newly colonized planets up to speed much more quickly (e.g. first build a few basic factories, then the more advanced versions). I imagine this problem gets worse later on. Hence, am I being penalized for becoming more advanced ? Or am I missing something here (e.g. you can still build them/ there are efficient alternatives)?