Your downloading apps I don't think retina matters. People who don't have touch 4 get retina and we don't now y'all want everything with retina do y'all want iBooks with retina or caculator? And don't get me started on Siri
Actually, yes I do want every bit of new software to take advantage of the higher end hardware that is made available. Why the hell wouldn't we?
If you can't afford or if you choose not to upgrade then that is your choice based on your situation and priorities. The rest of iOS users should not suffer because of your decision.
And the point of the OP was asking for the ability filter based on a criteria.