For gate production I would have thought a rebate block and perhaps a Euro cutter (tongue and groove / chamfer) block would have been sufficient depending on how elaborate the gates are. The blocks themselves are extremely cheap compared to router cutters and the carbide inserts / profile cutters are again a far cheaper option fir any volume work.
A decent power feed is a really good addition to either a router or spindle moulder so for me this is neutral. A router should have approximately the same cutter projection as a spindle moulder with limiters. They carry about the same user risk level as a consequence.
A secondhand SCM T100 would come in budget and probably with the tooling needed. As standard they have an excellent sliding table.
Having said all of that I would personally use a table saw to cut the rebates and I have a big spindle. The reason being is that it will actually be quicker, produce less shavings / with and create a useable strip to make beading if needed.